EDIT: Problem solved!
I've been using the same mods on my DST game for the past week and a half and have never had problems.
All of a sudden starting today (around 8pm PST) every time I try to craft something, the game crashes.
I turned off each mod one by one to find out if it's a single mod doing it but it seems no matter which server mod is activated, I get this error. All the mods are up to date and it only seems to happen when the server mods are turned on. Client mods don't have the error.
Have server mods turn on. Try to craft backpack.