I would say that many of the issues with Firefox for Android (Fenix) come from the fact that there are a lot of modular components that get managed by different teams. My experience is that whenever I've encountered a bug in Fenix that has a dependency on a GeckoView issue, it doesn't get fixed for at least a couple of months. Examples include the inability to copy magnet links and the inability to download images that need cookies attached to the request, like the ones for Cloudflare's DDoS protection. There is literally nothing I can do in those cases except use a Chromium-based browser. I may be biased, but in my experience having more than one repo with their own separate PRs and commit processes slows down bugfixes by an order of magnitude, even more so when they're managed by different teams.
For that matter, some other issues that have nothing to do with GeckoView, like breaking Bitwarden autocomplete and not restoring deleted tabs to their correct position on undo, haven't been fixed for even longer.
I think that Mozilla has good intentions, but they pushed out Fenix way, way too early, which broke the experience for users of previous version of Firefox for Android. And it seems that their mobile team is understaffed and overworked. I don't blame them, since they're essentially trying to create an entirely new browser (minus the rendering engine). But should be labeled as a beta, if not an alpha, in the state it's in - not "release-ready" as the version on the Play Store. It's proven that web browsers are too important in this era to get wrong when so much of our lives depend on them. If the experience is even slightly inferior to Chrome, the average user can easily switch and never end up using Firefox again.