I was having this bug where the game would just crash while trying to load my custom content on the loading screen which annoyed me a lot. I was trying different methods and then I found a way that fixed it (for me at least)

First you need to unsubscribe from all of your mods, have all of your mods in a mod pack first so you can easily get them back, then open Fraymakers, go to workshop (on Fraymakers, not steam) click the “view workshop” button, navigate the workshop menus so you get back to your collection with all of your desired mods and then subscribe to all of them, it will make your computer lag because of it downloading all of them but eventually your mods will be downloaded

After the mods are downloaded, exit out the window, and then click reload content (you might be able to skip this step but you can do this just to check that you got the mods)
Your mods should now be in the game without it crashing, you can close out of the game and then open it and it will boot up again!

Let me know if this works for you