For me the worst part is that you don't own the pocket-computers (PC/phones) that you buy.... please let me install an OS that I can trust.

there is https://wiki.galliumos.org/Hardware_Compatibility for ChromeOS devices but on many phones, it is currently not possible to install a 3rd party OS, unless you figure out how to root them yourself... and even then, some of its hardware will probably not be compatible because they don't release drivers

I wish a Librem 4 was available (a lot cheaper then the Librem 5)