Pretty much anything with XFCE, LXDE/LXQt, Cinnamon, MATE, a window manager like Sway or i3, or probably some others I'm forgetting, will work just fine. GNOME and KDE are the most popular but the slowest, and from what I remember, Deepin, Budgie, and Pantheon are somewhat slow.
LinuxSBC
This may not fit your needs, but matrix-docker-ansible-deploy is really good, and it uses Docker and Traefik by default.
True, but then it's complicated to install anything that's not available through a Flatpak, and a lot of online guides don't work. I love immutable distros (I use one myself), but I think they're best for either advanced users who can work around the quirks or basic users who only need the web browser and a few Flatpak apps.
At the very least, if Framework dies, many of the parts are standardized, and the ones that aren't are mostly open source. The SSD, RAM, WiFi card, and screen connector are all standardized. The expansion cards use USB-C and have an open-source shape; many people have already made third-party expansion cards. The motherboard has an open-source layout, and there are open-source CAD files to make custom enclosures (again, people have already done it). There are general schematics with pinouts on their Github, and they've provided exact schematics to repair stores. If they die, you end up with a laptop that is more repairable than almost any other, as well as a community with enough information to keep it alive if they want to.
Don't buy HP laptops. They're terrible. Framework is great, and Lenovo and Dell are generally pretty good. Put Linux on it if you care about privacy.
True, but how is that relevant? ABRoot has its own benefits and drawbacks over OSTree.
Yes, along with tons of other data.
That was true with Almost, but they've now switched to ABRoot, which uses overlays instead. https://documentation.vanillaos.org/docs/ABRoot/
Nix has "over 80 000 packages," according to their website. The AUR has 85719, so they're pretty close. This website seems out of date, as the AUR is listed as having 73914 packages, but it says that Nix is bigger. Either way, there's a lot.
GNOME with Pop!_Shell, Forge, or Material Shell works well, as does KDE with Polonium.