Quick update: downloaded newest version of mod from (mod downloading site, i forgot name) and added it to playset. Downloaded also version for 1.10 and tested in on that version.
Version 1.10 still works, 1.11 doesn't work

I suspect it's Mac-connected problem. From that point I don't have skills to continue checking what went wrong. I leave it here, maybe someone will help or someone will find solution.

Edit: Other 1.11 mods work, if anyone would want to ask in future

I use windows and have had that problem in the past, it was caused (for me) by the lack of a "ugc_(insert a lot of numbers)" text file and was fixed by simply deleting the mod and reinstalling it. I don't remember all of the details though, for example I can't remember if there was a ugc_ file that had to be deleted as well instead of just unsubscribing from the mod, or if I ever verified the integrity of HOI4s files.

The "ugc_" text files were located at Documents > Paradox Interactive > Hearts of Iron IV > mod, but this could be different on MAC so best of fortune with that.

And a games file integrity is checked by opening steam then going to Library > right click on a game > properties > local files > verify integrity of game files. (doing this will simply check the games files for missing or faulty ones and fix/replace them)

I do hope this will fix it but if not feel free to say so and I will try to help.

Oh and the way to know what ugc_ file to delete is by opening it and looking for the mods name in the text, so obviously look for and delete the one with Equestria at War in it. (if there even is one as im just giving as much potentially helpful info here as possible)

Alright, I think I solved it. Thank You Empress Chrysalis for pointing towards ugc files.

Short:
Don't try to have two versions of the same mod in the same time.

Long:
It turns out that every mod has its own number so Steam can recognize what files go where (like it is obvious).
But now I discovered that ugc/mod number DOESN'T change beetwen mods versions. What's more manually changing ugc/mod number in .mod files seems to have no impact on anything. That trick actually worked for me in previous releases, but Steam probably changed something.
So, if You want to play once old version and once new version, have another folder for old mod and move it in/out of mod folder depending if You want to play it or not this time.

Your very welcome! That would make sense for the mods at different versions to have the same number as if they were different it would allow the use of two of the same mod at slightly different but compatible versions (such as EAW being downloaded in 1.11.12 and 1.11.11) which would then double launch the mod and probably crash or confuse the crap out of the game.