old game version is not so impotrant. it changes almost nothing in mods. game crash source can be in old savegames OR wrong mods order.
Try to remove old saves temporary or load mods by one (for tests only). So, we can think about decision if will find problem

darkvoyager původně napsal:

My game crashes every time I try to load certain mods and I know why, they're compiled for an old version, so how do I recompile them?

Awkward is correct. Mod Crashes happen either because of incompatibility with each other or because a binding mod was removed from the load order.

there's this mod-unbinder that "can" help to try and salvage a character save or items when loaded at the top of the load order:
https://steamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=137868436&searchtext=unbinder

The more harsh method is to start the game launcher, go to the mod load order screen and while open - delete the entire Mod Save Folder then start the game - then exit.
The binds that crash the game will be removed.

I tried some testing (1 mod at a time) and it turns out that I can't even play the normal version, what should I try now? (I already tried reinstalling)

darkvoyager původně napsal:

I tried some testing (1 mod at a time) and it turns out that I can't even play the normal version, what should I try now? (I already tried reinstalling)

Documents > My Games > Runic Games > Torchlight_2 > there will be a local_settings.txt file. Delete it and try to start the game again. There's actually 2 of them. The other is located within the Save Folder. Delete that settings.txt file too and start the game again.

Inside Steam: could also right click the game name on the left side, go to Properties then Installed Files then Verify files to see if that helps.

Thank you very much for the help, The modded version works now!

darkvoyager původně napsal:

Thank you very much for the help, The modded version works now!

You're Welcome! Feel free to ask more questions on TL2 when needed.