> I ended up switching to Safari, to discover that it's just not quite as good an experience as Firefox or Chrome.

IMO, I find it to be just the opposite--neither Firefox nor Chrome are as good an experience as Safari.

Maybe the difference is that when a particular site does not work in a given browser, I don't blame the browser, I blame the website.

That's a bit presumptuous. My issue with Safari isn't that sites don't work; its seems comparable to Chrome in that regard. But using it doesn't feel as nice as Firefox or Chrome. It's harder to find features I need. Though to be honest, I find all browsers a bit lacking. I want more granular control over which cookies to accept and for how long, and how exactly to treat various sites.

And I certainly don't blame browsers for badly written sites, but blaming the site doesn't magically make it work either. Having less sites work for me is still a worse experience, no matter whose fault it is.

Safari seems to lag a lot in features. In compatibility it's a modern IE

Hardly. It took how long for Chrome and FF to support position sticky, or backdrop filter?

This is my experience as well. They are much slower to meet standards.

Spotify and some video sites do not work on Safari, which is mind blowing to me.

I just tried Twitter on iOS in Firefox where I have the strict privacy settings enabled including with Safari Firefox Focus content blocking turned on, and Twitter worked fine. In what way does it not work for you?

Firefox on iOS uses Safari's rendering engine. Maybe mcv is referring to Gecko-powered Firefox on Android?

I've been using Mobile Twitter on Firefox for Android and it works just fine.

I'm using Firefox on Android refusing third-party cookies, and for whatever reason Twitter doesn't work.

Twitter does work, just never the first time. After a reload it works.