Chrome and Edge make it simple to ‘install’ pages, so they’re easy to pin to the task bar. PWAs for Firefox gives that capability to Firefox, but it’s a bit brittle, and breaks easily if Firefox updates. It’s broken again for me tonight and the usual ‘reinstall this reinstall that’ hasn’t fixed it.
In my opinion Firefox took a significant backwards step when they killed that feature years ago.
I appreciate I might not be the target audience for Lemmy since I’m half Windows half Unix, and a Gmail / Keep / Calendar / Facebook / Messenger user.
The fact that it breaks so often might be a pointer as to why it was removed - sounds like it would be quite a maintenance burden.
However:
You might be in luck! https://connect.mozilla.org/t5/discussions/how-can-firefox-create-the-best-support-for-web-apps-on-the/m-p/60561
Wow, sounds like he gets it - just make tabs move able to task bar.