I mean, this one is on me. I bought Poco X3 Pro knowing damn well it's plagued with issues. But €188 for phone with Snapdragon 860, 120Hz screen, big battery, stereo speakers, headphone jack and IR blaster 1 and a half years ago? Hell, that sounds too good.
And yes, before you ask, I have tried turning it off an on. Also resetting both from settings and recovery.
I really preferred it on the right, too. It was the default on my Galaxy. But I have a Pixel for work and it doesn't seem to let you choose which side the back button is on. I can't stand to have an inconsistency.
Yeah from memory it was the default for Samsung, but stock Android had it the other way around. I've always preferred it, much easier to reach with my thumb while holding it in my right hand. I always swap it (custom firmware ensures this) and also have it set so a long press of the back button will force close any foreground app.
If you've got a Pixel phone I would look at installing GrapheneOS on it. Even if it's a work phone, chances are they won't know. If they find out, say you were ensuring the security of your device, for the benefit of both you and your employer.