You leave the game that is stressing you out.

I know. I know it feels like it’s not an option. But OP, you cannot be solely responsible for other people having fun. Especially at the cost of your own fun.

But ok. You’re not willing to do that yet.

Let’s start with something else then: be worse at backseat DMing. You get a private chat asking for help with character sheets? “Hi! I’m very busy this week, it’s probably better to check this with [DM] or [other player]!”

Your DM asks for help with monster stat blocks? “It’s been stressing me out a bit lately that I essentially know what’s coming in game - maybe you can ask [other acquaintance] or [reddit]?”

Stop doing the work that stresses you out so much. Yes, that might mean the game will collapse. But OP, you don’t need to be Atlas - holding the sky on your shoulders forever.