I find it impressive how negative people tend to be because something is not pure enough, they talk it down even much more than the duopoly systems. Yes, Sailfish OS has some closed source UI parts, and you can't just install desktop programs outside of the cli without running into problems. But running desktop programs, not optimised for mobile use are a terrible experience to begin with. This is a mobile device, not a desktop. If you disagree with that and want a desktop on your phone, there are options for you too, Sailfish OS isn't it though.

That said, what surprised me most is how much I am in the terminal on the phone and enjoying it. You'd certainly not going to have that kind of experience on an Android, also not on a degoogled one.