This is a bug in Google Play for web / PC / Edge / Windows 11.
When you analyse a source code of the Install button, you can see the following:

For some weird reason (a bug?) Google Play adds the following:
data-disable-idom="true" disabled=""
to the <button>
's code.
Removing this fragment and closing Dev Tools allows user to click Install button and continue.
Nothing unusual happens next. User goes through the regular: Verify, it is you + password + device pick + App will be soon installed path and naturally app is installed in about next 3-5 minutes.
&gl=US
just in case it's geoblocked.gl
parameter locks the geolocation of the Play Store listing and it may affect the app availability. This was with&gl=US
and this was without&gl=US
when accessing from Indonesia with Nexus 5 and Pixel 3a in the device list.