That might have been it. I played for around 5 minutes in the gray screen world and didn't get disconnected, I'll let you know if anything happens. Thank you so much for your help, time and patience
Honestly, the forums are a back burner thing. Not many people use it. Best option is discord. I know that I haven't looked at the forums for more then admin tasks in quite a while. You're also best off not following tutorials which give you code. Knowing programming and reading the MC/Forge code yourself would be the best way to go.
Task :runClient failed
Caused by: java.lang.ClassFormatError: Duplicate method name "lambda$renderItem$3" with signature "(Lnet.minecraft.world.item.ItemStack;)Ljava.lang.String;" in class file net/minecraft/client/gui/GuiGraphics
I was trying to find other forums with error like that but seemingly no one has encountered it
okay it was because i was using older parchment mappings on newer version of minecraft, the fix is on the parchment docs website