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Sorted Hearts

good

no, this was made years ago

doesn't require repentogon right?

Yep, that fixed it, cheers! :)

Deleting the mod files itself is never something I think of doing!

weird, I go to that line but it's just a basic function for adding a black heart, and "ModConfigMenuOptionType" doesn't appear anywhere in the code, though I remember that being a part of Config menu updates ages back, so I think you might have an older version, try deleting the mods files (Steam\steamapps\common\The Binding of Isaac Rebirth\mods\sortedhearts_1649552967) steam should re-download the mod

I do infact see an error message in the log.

[INFO] - ERR: ...g of Isaac Rebirth/mods/sortedhearts_1649552967/main.lua:144: attempt to index a nil value (global 'ModConfigMenuOptionType')
[INFO] - There was an error running the lua file: C:\Program Files (x86)\Steam\steamapps\common\The Binding of Isaac Rebirth/mods/sortedhearts_1649552967/main.lua

are you able to open the debug console when this happens? if so are there any error messages?

This mod seems to cause a softlock in the mod config menu, there is no options in this mod's menu, and when clicking into it, you can't click anything nor get out of it, requiring you to close the game.

After some extensive testing it seems this mod is indeed not the culprit! I can post the logs here but I don't think it would matter much. Thanks for all your efforts!
https://pastebin.com/XZyuajA2

https://imgur.com/a/3E3waXY
try deleting your local copy of the mod, if it still happens after steam downloads a fresh copy could you check your log file after a crash and tell me what it says?
(Documents\my games\Binding of Isaac Repentance\log.txt)