Yup. While I have a sceptical opinion of Ubuntu, it did find it sad that it didn't gain any traction. A possible contender is still Tizen OS. It's essentially an entire OS build around Chromium, while not owned by Google. Samsung use that a lot in their smart TVs.

Sure, it's not as performant as running native Android.

But boy have we seen some massive improvements in browser tech and performance increases on mobile devices. Developing web-applications is certainly a ton easier than native Android and IOS. Wrapper toolchains like React Native aren't helping much.

Unless you really need calls to some device APIs, there isn't too much left that a Browser can't do compared to what the native OS permits. I've been developing web-apps for robots and also developed equivalent native apps in Android. In the browser you now have access to some impressive 3d capabilities, which are extending further (BabylonJS). You've got the ability to interact with files via tool-chains that are not too dissimilar to what you see in native Android (Google has been clamping down file-system access to app devs quite heavily in recent releases). You can also gain decent API access to the devices battery and GPS status. Add some nifty UI libraries and you can provide a more pleasant experience, faster than with an actual native app. Even video streaming works remarkably well since you can interact with multiple cameras, microphones and even the screen (Google Meet does that).

It's now that we're seeing PWAs (progressive web app) to gain traction. I'm using Voyager for Lemmy, which works lovely in Windows and my phone.

In the browser you only miss on some native capabilities on some hardware component and a few legacy systems. Mainly serial communication and native UDP support. Although the last one will see some more improvements with HTTP3, which is gaining traction.