For example, I can hold my phone in portrait orientation, as well as both landscape orientations. What would be really nice is if there were some way to have the phone also in portrait mode but upside down.

As a former iPhone user, it made sense at that time because the notch would get in the way, but with Samsung (and especially their under-display cameras), it's a weird quirk. There isn't really anything in the way.

It isn't a dealbreaker if there's no way to fix it, but it totally feels like an oversight. I personally would find it useful to use my phone in portrait-upside-down mode so the charger is facing out and away, instead of sometimes poking me.