MacBook Pro randomly restarts into Recovery Mode, seems to be happening more lately

I have a 2017 MacBook Pro that I bought refurbished this past summer (May or so), and it has worked great for the most part, even after installing Big Sur. Within the past few weeks, I've noticed that it will restart on it's own (while the computer is asleep, I think) and go into Recovery Mode. And when in Recovery Mode, the startup disk is not visible. It seems to be happening more and more, and sometimes it has happened with a regular startup (as opposed to a Restart).

I've done multiple things, including reinstalling Big Sur, running Diagnostics and Apple Hardware Test (both of which came back with no errors, resetting NVPRAM and SMC, etc., None of which seems to have worked.

Another weird note: when it starts itself into Recovery Mode, it appears to be a Catalina Recovery Mode (it prompts me to reinstall Catalina, as opposed to Big Sur).