It's impossible to do that with the normal level editor. You need a specific dev only asset to do what you asked. If you want the dev assets, you should check out https://modbot.org/ and download the leveleditor+ mod.

I did this in one of my adventures. You need the storydifficulty trigger. It's the only way to detect story difficulty. It releases an output based on what difficulty you are in. There's 3 options to pick from, "Normal", "Hard", and "Insane".

You need to set up animations to play based on the storydifficulty trigger. You also need to place all the enemies you need in the level. For example, you have 2 sword1, 2 spear3, and 2 hammer5 in an area. Animation 1 will play when it detects the player is playing on Normal difficulty. What I do is make animation 1 keep the 2 sword1 inside the fight area. I also make the animation move the 2 spear3 and 2 hammer5 out of bounds and kill them. The easiest and most optimized way to do that is by playing the call method, "Explode" on the out of bounds enemies. Create animations 2 and 3 for hard and insane difficulty and follow the similar process, except keep different enemies in the fight area, like 2 spear3 on hard difficulty, and 2 hammer5 on insane difficulty.

Something needs to activate the storydifficulty trigger. Easiest way to do that is by having a "PlayerUseKeyTrigger". The player presses it, it activates the storydifficulty triggers, one of them will release an output based on your story mode difficulty, which will proceed to activate one of your animations that will set up the enemies. After that process is complete, you can let the player into the fight area. If you have a lot more enemies affected from the animations, you might want to make the player wait a few seconds before they are allowed into the fighting area.
(I can't remember if storydifficulty triggers can be activated by other triggers. If not, create an animation that activates the storydifficulty triggers, there will be a call method that tries to activate them. Again, it only releases an output if the players story mode difficulty is the same as the storydifficulty trigger).

This is a bit complicated to do, but it's the only way to take advantage of the story mode difficulty settings.

Seemingly can't get it to work, I have three story triggers, each with either normal, hard, or insane, I have 3 animated triggers as the inputs, and an animation corresponding to each. (Changes the position of a commentary camera to face "Normal", "Hard", ect.) Was wondering if I did anything wrong or have missed something important.
https://youtu.be/-TiSl3_7H1k

Seems like you never activated the animated trigger? You seem to be activating the "Only Play Once" on the animation track, but not the actual trigger. [Having clearer names can help avoid the confusion, for example, "DifficultyNormal" for the story trigger, and "TriggerNormal" for the animated trigger].

Just a thing to note with the leveleditor+ mod, it lets you animate any value not supported in the normal level editor. You can tell because the checkbox will be purple, as shown in the video.

Apparently I never needed those animation triggers, and that trigger probably couldn't be used since it can only be played in an animation. I just put the animations to the StoryDifficulty triggers and everything worked out fine! Thanks for the help.