Beat Saber is a pretty difficult game with pretty difficult achievements, getting an 8/10 rating on many achievement sites. Many people also do this game as their first VR 100%, and it takes a very long time to get good enough to accomplish all 26 of the achievements. But what if we could breeze by these achievements very quick? Using custom maps, we are able to obtain 23 out of the 26 achievements in the span of 25 hours. Everything that isn't a campaign achievement works, due to the fact of the campaign being its own gamemode. This is how you do it. No unofficial mods and file deletion are required, just installing custom maps which is allowed by the rules, meaning this is completely allowed under United Achievement Hunting Rules and will be valid on sites like SteamHunters.

To download the custom maps I have created, use this Google Drive link here[drive.google.com]. Download all of the folders present, as each folder is 1 map. You should have 17 folders.

To actually install the maps, head to your Beat Saber installation, which should be at:

Windows: C:\Program Files (x86)\Steam\steamapps\common\Beat Saber
Linux: ~/.local/share/Steam/steamapps/common/Beat Saber

Then, drag and drop all of the folders that you downloaded into the CustomLevels folder featured in Beat Saber_Data.

To check that you have installed the maps properly, boot up the game and go to the Custom Levels icon in Solo play (should be the 2nd icon), If you see 15 of the same map, Never Say Never from the Danganronpa series, and 20 minutes of silence, you've done it correctly.

If you need any help, leave a comment and I'll try to answer it as soon as I can.

For a brief description of what each map is,
The free song maps include a Normal/Hard/Expert difficulty with 1 simple note each and are meant for the achievements where you need to obtain a rank, use modifiers, clear 100 maps, and full combo and SS rank 15 unique songs on Hard and Expert. That is why there is 15 of them.
Never Say Never includes a Normal/Hard/Expert difficulty and is meant for the specific combo (50/100/500) achievements, farming 100m score, and farming 10k good cuts.
20 minutes of silence only includes an Easy difficulty and is meant for the sole purpose of farming the 100km hand movement and 24hr of playtime achievements.

Now, to get started, I'd complete the tutorial first. It only takes us about a minute and will get us our first achievement. It should also help you understand how the game works. You should see it upon starting up the game for the first time, but if you dont, you can find it by pressing the question mark and clicking the play tutorial button.

1. You Are Ready - Finish the tutorial.

Now head to solo play. Start up the first free song map on Normal and cut the 1 block of the map with a big slice through the center in order to obtain a SS rank. Repeat this 4 times with the Faster Song, Disappearing Arrows, 4 Lives, and 1 Life modifiers (you select a modifier by selecting it to the left of the song selection screen before selecting a song) to obtain these 6 achievements. This whole section should have taken you about a minute.

2. Pure - Clear any level without any modifiers.
3. Good Enough - Get at least rank A on any level on normal difficulty without any modifiers.
4. Faster - Clear any level with the Faster Song modifier.
5. Memory - Clear any level with the Disappearing Arrows modifier.
6. On The Edge - Clear any level with the 1 Life modifier.
7. Charge - Clear any level with the 4 Lives modifier.

Now, head to the Hard/Expert difficulties of those songs. You must repeat the process of finishing the song 15 times for each difficulty, and since there is achievements that require you to not be using any modifiers its best to turn them off. After finishing 1 time, make sure to move to the next copy of the song, because the achievement only tracks unique songs. They are all identical, dont worry. Make sure to do nice and big swings that connect with the center of the block and pass through the block, so you can obtain SS ranks easily. After doing this for about 10 or so minutes, you should have easily obtained all of these achievements.

8. Special - On hard difficulty, Get at least rank S on any level without any modifiers.
9. Precision - Get rank S on at least 15 different levels on hard difficulty (solo free play only).
10. Drum Kit - Get full combo on at least 15 different levels on hard difficulty (solo free play only).
11. Expert - Clear any level on expert difficulty without any modifiers.
12. Supreme - Get full combo on any level on expert difficulty without any modifiers.
13. Flawless - Get rank SS on any level on expert difficulty without any modifiers.
14. Hope - Get rank S on at least 15 different levels on expert difficulty (solo free play only).
15. No Mistakes - Get full combo on at least 15 different levels on expert difficulty (solo free play only).

Once you do that, head to Never Say Never. I have specifically put enough blocks to cut here for each combo achievement (and also a few more). They are all in the same spot, so just keep shaking your sabers so that the game properly registers a hit. Make sure to play without modifiers. After playing through each difficulty, you will obtain these 3 achievements.

16. Pay Attention - Clear any level on normal difficulty and get at least 50 combo without any modifiers.
17. Concentrate - Clear any level on hard difficulty and get at least 100 combo without any modifiers.
18. Focus - Clear any level on expert difficulty and get at least 500 combo without any modifiers

Now. it is farming time. It's fair to take on the campaign at this point, but if you want to have everything before doing the campaign, heres the order you should do these in.

19. Warm-up - Clear 100 levels or more.

Put on any of the free songs on the Faster Song modifier, and then grind this out. Since the free songs are only 10 seconds (7 with the modifier), this won't take long at all.

20. Drill - Get total 10,000 good cuts or more.

A good cut is what contributes toward combo. Pull up Never Say Never on Expert with the Faster Song modifier, and then repeat the song until you've gotten this. Should not take long at all considering you get around 750 cuts per runthrough of the song.

21. Traveller - Get 100 kilometers of travelled hand distance or more.

Put on the 20 minutes of silence song and go absolutely crazy with your hands. Shake as much as you can without getting physically exhausted. You may require a couple playthroughs of the song.

22. 100 Million - Get total score 100 million or more.

Pull up Never Say Never on Expert with the Faster Song modifier. Even with weak cuts, you should be able to get about 300k score in a minute with the song. This could probably be further optimized, but I wanted to keep the map not heavy on performance. (Since there is an effect each time a block gets cut.) Alternatively, play this[beatsaver.com], which can be very physically demanding but has the potential to easily get you about 2 million within 3 or so minutes.

23. Day and Night - Get total played time 24 hours or more.

I recommend this for last after you've done everything else and the campaign since you will earn progress towards this achievement by doing all of those, and it would make your experience worse if you still had to play the campaign even after getting this.
Put on the 20 minutes of silence song, hit the one block, and leave your VR going to complete the song. I recommend having a timer for each time you have to restart the song. For an alternative, use this 3 hour song that you can find here[beatsaver.com], This map will cut down heavily on the amount of reloads you have to do. Just make sure to turn on something like No Fail or Zen Mode.

After doing all of these, you have to complete all levels in the campaign, which cannot be cheesed in any way. So just try your best and have fun. This is the most challenging part of the 100% now.
Completing the campaign will give you these 3 achievements.

24. Progress - Clear 30 missions in campaign.
25. Not the End - Clear final mission in campaign.
26. Peace - Clear all missions in campaign.

Now you have 100% :) Thanks for reading, and leave a comment or an award if this helped you out!