Issue is what the title is, when I tried pressing u the game crashed and the report is here: https://pastebin.com/H878srWG. I'm using 1.16.5 and the most up to date creative core and cmdcam. I've reinstalled several times and no luck.

Update: As it turns out, the creative core was not up to date. I wasn't aware of it because the downloads weren't organized in the correct order. I would suggest changing that.