I'm going to add my two cents in here about the battery...... This past weekend I just came back from Samsung Customer Service after they replaced the battery in my Note 9. The battery swelled up so much that the back glass lifted about 1cm exposing the inside. It actually hasn't been 2 years since I've had that phone because I recall mine didn't get delivered until October with the shipping debacles from 2 years ago. The reason why I mention this is...
Last year around exactly THIS time, I had the Samsung Customer Service center replace the battery in my Note 8 because the battery also swelled up so much that the back glass lifted about 1cm exposing the inside. The phone was also at that point about 2 years old. It's has since been traded in.
So, I'm not trying to say anything about the batteries because since there has not been widespread swollen battery issues (that I've noticed), but it's uncanny that this happens to me two years in a row. I am chalking it up to something that I must be doing - but I can't figure out what since I don't charge it when it doesn't need charging. I typically let it go through a cycle before recharging. I don't do anything special. I don't leave it plugged in forever. I actually do not use Fast charge all the time since most of my chargers were not. Perhaps I am just unlucky, but hell if it happens to my Note 10+ next Aug/Sep.... I'm going to start wondering really WTF?
The only other time I've ever had a swollen battery issue with Samsung was with my Note 4 batteries which swelled after a number of years by themselves without even charging - but those were removable and I didn't need to visit any service center.
All of this swelling always happened when it was not plugged in for charging, too.