What I think damages Firefox's user-friendliness more is how easy it is to get to setting screens that look scary to the average user. For example Firefox recently started recommending an extension called "Enhancer for YouTube" when a user visits YouTube after upgrading to some new version of Firefox. Upon installing the extension, you get taken to the extension's settings screen which has a design that would definitely throw off my non-techie family members [1]. Also, take a look at the Firefox release notes for iOS [2] – sure it's "nice" for us devs to have access to raw GitHub issue labels or whatever those are – but for non-techie users they might be interpreted as conveying a certain messaging that Firefox is not really designed for them.
[1] https://i.imgur.com/8TIetRA.png [2] https://i.imgur.com/QoUG1ZF.png
I want to love it, but even after a fresh install of MacOS every time I go to use it on my 2015 MBP it grinds to a halt.
I'm sticking to ungoogled-chromium for now. I really hope it's resolved down the line!
Personally, I've use Firefox as my primary browser since before I started using Macs, and after 6 different Macs between home and work, I've never had any problems with it.