M1 MacBook Air Randomly Shuts Down

My MacBook is only a few months old: the battery has a whopping 55 cycles on it. I mainly use it for research and writing, as that's my job.

Frequently, I'll pop off to make some coffee or something. When I come back, the machine is off. If I've been lucky enough to leave something unsaved, that will be the only reason the whole machine didn't shut down. I often leave an open, unsaved Word document with a single 'e' in it, just in case.

My battery settings are optimised for its health, but I can't find any settings in there anyway to prevent this from happening. I've searched through this community for solutions, and can't find a single thing.

Sure, I'm happy for the thing to sleep if I'm not using it for a while. But if I'm making coffee or tea and I come back to find every tab, and the browser I used to set up for a Teams or whatever call in 3 minutes, have suddenly disappeared into the ether, my goat is well and truly got.

Please, is there anybody out there with a similar machine, the same problem, and a solution?

I'd be most grateful indeed.