Bizarre decisions about features is run of the mill these days for Mozilla. I had to use FF a few days ago (WebKit derivatives can't load massive GitHub pull requests) and I truly missed the browser. But I use PWAs, so I have to use Chrome.
I'm not sure why you find Chrome necessary for PWAs, I use Discord, Spotify, Zoom, etc. all exclusively from within Firefox.
That's not what a PWA is, a PWA is installable, and Firefox doesn't have that.