No, the phone variant of HarmonyOS runs on top of a Linux kernel.

I believe thats being phased out slowly to be native app only with their multidevice HarmonyOSNext (mobile/pc). Once the major apps move over , last bits of linux will be excised.

Nope, the new version removed it.

https://en.wikipedia.org/wiki/HarmonyOS_NEXT

Indeed, I did not see that!

Can it run all of the kinds of apps that people (in the EU/US markets, which is relevant to the discussion at hand) actually want to run? SalifishOS doesn't even do that, at least not for me.

If I remember correctly they have had a translation layer for android apps since they launched. But it's similar to what Apple has done with Rosetta 2 where it getting phased out for native apps only.

The will to create an OS is 0.0001% of the problem. There are tens of thousands of applications that people need to use that exist only for iPhone and Android.

There are dozens of functional mobile OSes. And OS isn’t useful unless it has application support for the tasks people want to accomplish, though.

...if there is will, a nice state sponsor and an already existing effective infrastructure.

Europe has none of the 3.