That depends on the usage pattern. To give you a totally different way to use Firefox: I use it both on desktop (Linux) and on mobile (Android, multiple devices.) I don't ever close it. I close it to update or to reboot my computer. On desktop it's configured to restart with the previously opened tabs and windows (one per customer, each one on its virtual desktop, one for me.) I don't sync tabs because way more than half of the tabs on my desktop Firefox are related to work, some localhost, some reachable only on a VPN. Furthermore it's no business of Mozilla or anybody else to see my tabs go through their servers, E2E encryption or not. I never used any browser internal password manager because (any other considerations apart) what happens when I want to access a site from another browser? Maybe from Chrome, and I used Opera and Vivaldi as secondary browsers many years ago. I store my passwords in one of the various Keepass apps, sync from desktop to mobile with syncthing and I'm happy.

Firefox as browser-only browser is perfectly good for me. The surrounding UI is almost transparent to me, as if it did not exist.

The only point of contact between your and mine experiences are the bookmarks on mobile. I don't use them. I pin the sites I use most on the page that opens when pressing the new tab button and those are my bookmarks. Unfortunately there are only 16 possible pinned sites there but I'm not even using all of them. Most of the times I tap the URL bar, type one or two letters and Firefox autocompletes the sites I want to see. Example: I tap n and it suggests news.ycombinator.com. Faster than any bookmarks menu.

Anyway. If most users follow your workflow, Mozilla are not doing a good job. If most users follow my workflow, they are wasting a lot of engineering time in features we don't use. IMHO Firefox users are mostly power users so I think there are at least ten different workflows competing for the top spot and whatever Mozilla does people will be mostly upset. It's not an easy place to be.