Ubisoft is turning off the servers and not letting us buy or even access content we already bought if we start a new game. so here is a few save files for both Uplay AND Steam.
Also with it is a Uplay save that has online rank max.

Video Guide
https://youtu.be/txfQgawQCvk

Game is a completed save file. so it WILL overwrite your current save. Make sure to backup your existing saves.

Uplay
1. Launch Uplay
2. 3Line dropdown menu
3. Settings
4. Uncheck "Enable Cloud Save"
5. Restart Uplay

C:\Program Files (x86)\Ubisoft\Ubisoft Game Launcher\savegames[Account ID]\91
or
C:\Program Files (x86)\Ubisoft\Ubisoft Game Launcher\savegames[Account ID]\449

1.save
2.save
are the files that you need to replace.

1. Launch Uplay
2. 3Line dropdown menu
3. Settings
4. Check "Enable Cloud Save"
5. Restart Uplay

Select Local Save and your save is now in the Uplay Cloud.

Steam
C:\Users\[USERNAME]\Documents\Ubisoft\Blacklist\Save\SAMFISHER


inside you will see 2 files sc6_save.sav and one that is a BAK file
replace those after you back them up.
then when launching via Steam select Local Save and itll upload the save to the Steam Servers.

Ok so questions are asked heres the answers sorry for the wait.
1. Yes this will overwrite your save make a back up game can be replayed with every item via map screen
2. EVERYTHING is unlocked, Missions, Weapons, DLC and Uplay Rewards
3. If you click "Restart Story" itll get rid of your DLC and Uplay Rewards as well (why i recommend the save and to backup your own save as well)
4. Yes works with the Standard Edition. I own the Deluxe on Uplay and restarted it and lost all content. Bought the Standard Steam version when it was on sale and it was the same. missing content. tried it with both. worked on both steam standard edition and Upay Deluxe edition.
5. People in the youtube comments AND nexus comments say it work and confirm it works
6. 3 saves as uplay and steam use differemt files for saving. the 3rd is my max online rank save for uplay for MP before servers shutdown September 1st.
7. Dlc and Uplay rewards will still work after September 1st using this save file.
8. Any questions on how to install refer to the video.

Hope this helps. Ive been talking with Ubisoft to TRY to get a fix. like Start a new game and the save file thats created auto unlocks the dlc and uplay rewards from the get go, infact some Uplay reward content isnt even accesible currently. and its not September 1st yet.
I did make a forum post on Ubisoft Forums per Ubisoft Support on Twitter recommend. BUT i feel they are giving me the run around.

I found this post
https://www.reddit.com/r/Splintercell/comments/w1muyu/updated_infoguide_for_editing_blacklist_save/
From looking around its just a toggle in the save file itself.
and from what it seems from the DLC item thats unlocked from the now defunct Spider bot Android and iOS game,
https://splintercell.fandom.com/wiki/Splinter_Cell:_Blacklist_Spider-Bot

"The game was retired as of January 2016, and neither it nor the Alpha Goggles or Alpha Boots are available."
Yet as you can see in the save file in game and even in the image i uploaded to Nexus mods site, the "unavailable DLC" is unlocked and working.



Basically the Deluxe Edition only existed to sell you content that was already included in the data as "Pre-Order" bonus on release or in the collectors edition (the one with the RC plane) https://www.ign.com/wikis/splinter-cell-blacklist/Collector%27s_Editions.
https://www.ign.com/wikis/splinter-cell-blacklist/Pre-Order_Bonuses ( https://youtu.be/RKaCcYfVt9c?t=117 video footage of Preorder bonus on ps3 and Xbox 360 even)
https://en.wikipedia.org/wiki/Tom_Clancy%27s_Splinter_Cell:_Blacklist
"Announced at E3 2012, the game was released worldwide for Microsoft Windows, PlayStation 3, Wii U, and Xbox 360 in August 2013."
Game came out on PC, 360 and PS3 at the same time btw.


TLDR
Yes it works on standard edition, will overwrite your saves, its not modified, merely 100% complete Items and mission completion with all DLC and Rewards unlocked as thats all saved in the save file. Through learning of editing the save file i learned its just a toggle in the save file that unlocks the DLC content in the full game as its all up to date with all content when you buy it on steam. It will work after September 1st more than likely as one item in game thats not available due to an android app being defunct called Blacklist Spider bot.

Hope this helps everyone! Have a great day!