Essentially you are (or were didn’t have time lately to check) locked to home assistant os.

Since when? I use it frequently in my house. The possibilities are damn near endless, you have the freedom to do damn near whatever the fuck you want with it.

The problems come with shitty vendor integrations that intentionally gimp functionality when the devices aren't used in whatever "official" app the vendor ships. That's not HA's fault, tha's squarely on the vendor for doing shit in bad faith to steer low-IQ customers (like you, apparently) to the "official" app.