Every now and then I download Firefox and try to gaslight myself that it's actually a good browser now. It usually doesn't take long before I'm using a chromium based browser again.
I also encounter way too many bugs and weird behaviours in Firefox web dev tools. I hate chromium dev tools too, but I find it a more consistent bad experience.
The closest I've been to fully switching has been Zen browser. The ability to completely hide the browser's UI so you only see it when hovering is almost good enough to forget all other issues I got with Firefox. That "focus mode", vertical tabs, and side-panels, are the best UI elements to come to browsers since tabs, and I hope and expect all browsers copy them soon enough.
(edit: sorry you were not talking about bugs, was confusing with another reply in this thread)
That is probably the biggest reason most people stay with Chrome. When Google created their browser and did their big global campaign they got most people used to using their browser, and now it's hard for people to move away from it, so they can make changes to the browser that are profiting for them.
It's up to the end user to decide if it wants Google to guide their internet browsing experience, or that it rather joins a more open and independent community.