@qyliss I have the same goal. I am getting a Librebooted thinkpad and a PinePhone.
Right now I basically have a tablet with a keyboard. It is an Amazon tablet, but I was able to neutralize most of the hostile applications.
The best thing is to just not use nonfree software to begin with. Fortunately I never became very attached to proprietary systems (for example, I never got a Facebook account or used a Mac). Before my computer broke, the only nonfree software it ran was the kernel firmware plus whatever garbage the BIOS and Intel CPU had.