So, I just learned about this the very, very hard way.
After buying a second hand S10 and finding american ones can't be unlocked, traveling 4 hours to buy another one after much research, much annoyances to unlock it (samsung requires you to be online, which I didn't know) and testing multiple ROMs, I finally read this page more properly https://wiki.lineageos.org/devices/beyond1lte/ which says "known quirks: IMS". I thought it was just something like dolby sound.
What it means is that it doesn't suport VoLTE and most currently used phone systems. Samsung made their proprietary mess, unlike most other developers, which means it will probably never have an open source version.
And that applies to ALL modern samsung phones. I had samsung phone before with a custom OS, but didn't realize because VoLTE wasn't mandatory back then. Now it is here in Australia, and many countries. So if you ever plan to buy a samsung phone to degoogle it, know that it won't make phone calls. SMS and mobile data also doesn't work.
I don't know how I missed this. It should be talked more often given how popular samsung is. There should always be a warning "YOU WON'T BE ABLE TO MAKE PHONE CALLS IN THE FUTURE IF YOU CONTINUE".
S10 was the last decent phone ever made (for me). Not too big, SD card, headphone jack (one of the most important things for me), good camera, etc, etc... That's why I was so persistent to find one to degoogle.
So I'm stuck with my amazingly shitty pixel 5 (and other ones are even worse for me). And considering the possibility of a life without smartphones at all, since this is a losing battle. Mainstream doesn't care and evil companies have every incentive to kill freedom. It has been getting really bad and it will just get worse. But anyway... this post is not about this.
Be warned, if you care about freedom don't ever buy samsung again. Not because they are evil (they are), but because you won't be able to make phone calls on your "phone".
Oh, setup is easy. I actually even enjoy setting up a new phone.
I have all my files and messages synced on syncthing constantly, and contacts and etc on DAVx. Even apps, most from f-droid, are a few clicks from a backup. I can do the whole thing in a few minutes, but I enjoy taking longer.
The issue with finding a phone that I can unlock and installing a working ROM instead, that's the issue, and it should not have to be like that at all. That's what is becoming impossible and making dumb phones a better alternative.
Ah, and the money too. Which is why I never buy expensive phones anymore. I know I'll lose it, drown it, kill it. That's another good reason for dumb phones.