Firefox Focus has been my go to browser on iOS since the time it launched. The premise is a single tab, which you use and then erase all data from once you're done. As it says, rinse and repeat! If you want multiple tabs, this is not the browser for you (though Firefox iOS could be).

I use Firefox Focus more than any other app, including for browsing and reading through HN comments. It's got a good ad blocker (though not the fastest [1]), but no options to control ad blocking on a per site basis.

The browser has been improving over time. It also includes an extra layer of passcode/biometric protection that can help prevent others from seeing what you've opened in it. The only issue I've noticed is that it sometimes forgets the page you've loaded after sometime (may be because it doesn't save them to the disk, and when iOS removes it from memory, it starts out again as a blank slate).

[1]: https://brooksreview.net/2018/09/safari-content-blocker-eval...

I've used it for a couple months now. It's great, and I can't remember any sites that plain didn't work, though some were pretty ugly.

The one thing I miss is tabs, which FFF doesn't seem to have.