Majorly infuriating.
It's not really your phone if it does things like this. This is Samsung's phone you pay for their permission to carry for a few years.
True ownership means fully possessing something and deciding how it operates including what software it runs, what data that software can access, and when it can access it. I would not be surprised if those apps had some very invasive default permissions.
When you first switch you might feel overwhelmed because you'll have to develop a sense of how things work in a non-Windows world. But, after a bit you'll realize you feel in control of your computer, maybe for the first time ever. It may seem like a small thing, but the realization that I finally "own" my computer and control the software that is installed on it, how it runs, what programs do what tasks, etc... was really surprising and made everything worth while.
As for switching, I had been exploring the idea. One night while writing an important work email on my Windows 11 pc in outlook (also work required) my pc just randomly shut itself off and, of course, outlook did not save the email draft. Deleted the windows virus the next day and my pc has worked much better ever sense.
If you make the switch you'll be able to find lots of great help with technical issues online in places like this.
It's free for a limited number of personal devices. Add the jellyfin server to your tailscale network and it will receive a local ip. Add you grandfather's roku (or possibly router) to that same tailscale. You'll then be able to enter the Tailscale ip address of your jellyfin into the roku app to get access.
I don't have a roku, but use tailscale to access several home services while I'm out including a jellyfin instance. It is incredibly easy to setup and use, particularly if you are limited by complex router situations.
"Wants to become a full paranoid but fears the slippery slope."
I feel personally attacked yet fully approve this characterization.
Congrats on making the change!
One piece of gaming software I have not seen mentions yet that I really like is Lutris. It is a unified launcher (steam, gog, epic...) that really helps to keep game installations organized and also helps to manage wine prefixes. I recommend checking it out.