Android shouldn't be considered Open Source anymore, since source code is published in batches and only part of the system is open, with more and more apps going behind the Google ecosystem itself.
Maybe it's time for a third large phone OS, whether it comes from China getting fed up with the US and Google's shenanigans (Huawei has HarmonyOS but it's not open) or some "GNU/Linux" touch version that has a serious ecosystem. Especially when more and more apps and services are "mobile-first" or "mobile-only" like banking.
It's been that time for years. But it's easier said than done. The closest we've currently got are the various phone-targeted Linux distros out there. But they're not quite ready for serious usage for me; at least not on the Pinephone. Still, that's where to put your time & money if you're serious about wanting a change.
And while efforts like Pinephone are good, they don't have the VC or talent to really make that a reality anytime soon on a massive scale. Most efforts in this space are open source which is great but doesn't really pay anything. People with these skills can easily work at any phone OEM and make good money. So I think it will take a massive company to do it. Maybe Microsoft wants to give it another go haha. Amazon has tried multiple times to make this a reality but it's just cost so much money and time that they keep shutting it down.
I don't have any answers, for something to become viable is has to appeal to the average consumer and getting to that point is like crossing a mountain.