MacBook Pro Randomly Shutdown & Won't Charge / Turn On?

My MacBook Pro hadn't been charging properly - when on charge it would decrease in battery / stay at the same charge unless I left it to charge and didn't use it (it would then charge very slowly). Last night (while on charge at 6%), it turned itself off. I tried to charge it after that (using two different charging ports + cables) and it still won't charge.

Ironically, I checked the battery life just before the MacBook turned itself off and it was normal. I've ordered a new charger in hope that helps but I can't imagine it will as I've already tried 2 chargers.

This was a day after the Big Sur update if that makes a difference. Has anyone else experienced this recently?