He’s pretty much the quintessential QA tester. He wants to do things his way, regardless of whether or not the OS wants him to do that. He’s usually skilled enough to fix anything he messes up, but he doesn’t know enough about Linux to do that, so he ends up breaking things. I feel like most people have a better experience than he did, but his technique uncovered a ton of bugs and usability issues that significantly improved the Linux desktop to have fixed.
Have you installed a custom ROM on it? If not, you definitely don’t have the skills for this. If so, have you built your own ROM for it? If not, do that so you learn how it works in a predictable environment. Then port something existing to it, like UBPorts. Only after you do all of that and probably a lot more should you attempt to effectively develop your own distro on hostile hardware.
Tiling addons. I like having a full DE, but I also want tiling, so Pop!_Shell on GNOME and Polonium on KDE are invaluable (and yes, COSMIC looks really promising).
VanillaOS and BlendOS also use containers to install apps, just like Fedora Silverblue. In fact, it’s easier to install native packages on Silverblue than it is on VanillaOS. Just set your terminal to start a container by default.