First photo I take using the S21 is after midnight. As usual, the subject is my previous Galaxy phone...or should I say phones. I kept Valerie's Galaxy S7 as a backup device , mainly so I could continue to use it with GearVR (which could not support newer phones because it used micro USB). As you can see here, the size difference between the S7's 5.1 inch screen and S9's 5.8 incher was even more obvious because Samsung ditched physical buttons for additional screen real estate. It's funny that I have owned only odd-numbered Galaxy phones (starting with the S3)...because, due to Samsung's naming-scheme change, their last two models were both even numbered (S10 and S20).
While Samsung's Smart Switch app continues to make transitioning from Galaxy phone to Galaxy phone far easier (and quicker over wifi) than before, there are still many things that require intervention. Yes, all of my data (including from the microSD card) made the jump to the new phone (I backed up the microSD card to my computer because I wasn't sure it would). Most of the apps carried over, but some (like Nova Launcher) required manual exporting and importing of settings...which is why I am glad I can take my time and make sure everything is working before I send in my old phone. Various two-factor authentication methods also add to the challenge as not all methods simply call the phone number.
Note that I made the mistake of removing the microSD card from the S9 before exporting my music playlist. And to think, I switched from Google's music player to Samsung's specifically because I could transfer playlists from one phone to another...