Honestly, I have no idea. Maybe categorizing things into MVP, standard, and advanced would be a good start.
When I think of most apps on my phone, these capabilities are rare or non-existent:
- USB
- AV/VR
- Payment processing or IAP (almost certainly my own tastes here tho)
- Window management(?) - I'm not even sure what this means on mobile.
But obviously, whatever deficiencies exist in background work or notifications are probably important. Looking at CIU, Firefox seems to have resolved them in more recent versions. In fact maybe some other comment has already mentioned it but FF/Android 141+ seems to have resolved a lot of those?
I think I understand the deeper point you're trying to make, which is that not all web platform capabilities are created equal when it comes to making PWAs a legitimate alternative to native apps.
I've tried to be thoughtful about this, and my solution was to weight the capabilities from 0.5–3. At the two ends of that range, I gave required PWA features a weight of 3, and nice-to-have/experimental features a weight of 0.5. As you can see, this doesn't really penalize Chrome for its "stunt features", and I think it provides a more realistic picture of what Firefox and Safari are capable of for most PWA use cases.
Additionally, experimental and non-standard features aren't used to compute the PWAscore. You can see raw scores (unweighted, and including experimental/non-standard features) in the tooltip of the "normal" score.