Game crashed while initalizing game

The game crashed whilst initializing game
Error: byx: Unable to fit: minecraft:blocks/diamond_block - size: 256x256 - Maybe try a lowerresolution resourcepack?
This is the message I get whenever I try to open the game. The issue is, I can't even access my resource packs as far as I can tell. So how am I supposed to fix the problem when i can't even get to the part that lets me address the problem???? Literally nobody else seems to be having this issue, so how am I supposed to fix this?