When I was considering what to run, I found LineageOS TV provided the best experience for being able to get all the other TV apps, and even Jackbox Games. Many TV apps offer some content free with ads, which can be taken care of. Android TV interface only shows Android TV apps in the main app drawer though.
I loved Debian with KDE Big Screen on the pi for the customizability. You can run scripts like fetching tv schedules right on it (or you can just do this on your jellyfin server), and generally you have more customizability. I run PWAs as well via Firefox. I found Steam Link difficult to get working unless on Buster or earlier.
For remote, I tried out all the ones on Amazon, and found USB connection to be most reliable, and there's one that has a keyboard on the reverse, and an option to do voice control from the remote that's a major 🔑
Debian with KDE.
Debian because it is (one of) the most established distro(s), stable releases, most distros are based off of it for a reason, you're not forced to deal with Snap packages (I recommend Flatpak via Flathub, but Appimages and .Deb files are common options too).
KDE gives you that Windows look (other popular one is GNOME if you prefer the MacOS look). It's the desktop environment people often confuse with as the distro, so don't go necessarily by how it looks as you can easily change that.