When I try to play a modded version of minecraft using curseforge with a modpack that I put together myself it crashes immediately.

I have no idea what this means or how to read the bug report and when I tried launching a regular installation in that same launcher it had no problems. When I tried playing with a premade mod pack it worked fine. I have absolutely no idea what's going on or even remotely what any of the crash report means. I've tried using different combinations of the mods/resource packs/shader and nothing has worked. Vanilla Minecraft works just fine and the only time it crashes is when I use the specific modded installation. Also I tried to enter 1.20 in the "affects versions" category but it wouldn't let me.