The s23 plus is my go to recommendation of this year. The s22u has horrible battery in comparison. The only difference between the s23 plus and s23 ultra that matter (to 99% of people) are the boxier slightly larger design, 10x camera, and spen. If you can live without those 3 things then get the s23 plus. I am a very heavy user and I got the s22u because it promised great efficiency gains over the s21u (I wish that was actually true). I had to get a magsafe battery in order to get through my day. An s23+ would serve you much better then an s22u would.
That seems like a massive headache. There is absolutely no reason to do it monthly. You would never be able to store any pictures, videos, or apps on the phone. You would be constantly reinstalling things. That just seems awful. You don’t need to. You don’t even need to do it for major os updates. Some people do and it’s fine I just see it as unnecessary.