None of these are available on platforms other than iOS or Android, unfortunately. Some of them have web experiences, but they're terrible on mobile when compared to their app.
I, too, would love to run a mobile-optimized Linux desktop on my phone, but it's not about the desktop, it's about the apps and functionality it gives me access to. So I'm stuck with Android for the time being.
What would be really cool is if these alt mobile OSes could perfectly emulate Android to the point that Google's SafetyNet would believe that everything is a-ok. Not sure if that's even technically possible, but could help bridge the gap and allow alternative OSes to gain some market share among people who aren't willing to give up many of their usual mobile apps.
> What is an ideal phone for you, and how would Linux help achieve that experience?
The main bits for me are privacy and control. I refuse to use an iPhone because I viscerally hate Apple's stranglehold over the platform. I very reluctantly use Android, hating that Google is always watching. A fully-open mobile OS where I get to choose what runs on it, how it runs, and what access it gets would solve both of those problems.
Primarily, I want software I can trust, because I trust that the developers' motives are aligned with my own: a useful tool that I'm in control of.
In my experience, most Free software fits that bill; whereas most proprietary software seems more interested in persuading me to buy something or sign up for something that I don't want. (Most, not all; I can think of counterexamples.)
Bluntly, Free software is usually much less full of skeevy bullshit.
Yes and it's amazing how much smaller, faster and battery-efficient it can be without all the marketing and tracking crap.
Most apps on F-Droid are a few MB as opposed to tens of MBs for the play store ones. Most are well written and efficient. The quality of these has really increased the last couple of years.