I use Vimium plugin to navigate web pages. gg brings to the top of the page whereas Ctrl + G brings me to the bottom.

C-g? Does that also work, or did you mix up G/S-g?

This is probably the Vimium feature I use most often!

It really bothers the fuck out of me that I can't find any iOS browser with a back to top feature. It makes browsing far more annoying than it needs to be and I end up not bothering.

Double tap the address bar in Safari. This goes back to top.

edit: or the status bar (tested on iPhone XS)

It doesn't really work. It's just fiddly and often doesn't do what I want it to. I don't even understand how it's supposed to work. I tap at the top so the address bar shows up. I tap the address bar. It thinks I want to enter a URL, so it changes the view.

You're supposed to tap at the very top, near the time or the notch depending on what device you have. This works in all apps that use standard scroll views.

Double tap not on the address bar but above, on the time in the OS top bar.

Works on ios chrome too, but for both it breaks down when a call/gps banner is up there

Even more: it is a global feature that is supposed to work for any view controller with a scrollable view. (I wouldn't describe it as "double tap", though: you tap the status bar once, but in Safari the status bar is hidden as you scroll down so you have to tap the top of the screen to reveal it.)

I usually use the home and end keys on my keyboard.