The iOS app does not have loop mode.

Safari browser on my iPad can sort of try to do loop mode but adjusting the A and B markers is inconsistent at best and mostly just doesn't work.

On my work laptop, I am able to get the loop mode to work in Firefox no problem (though it isn't a great UX) but it is my work laptop and not really for my personal use.

What is the best mobile browser for the site, especially for the looping feature?

I still hope that GT at some point in the future moves to Sound Slice technology. Works perfect on desktop browser, mobile browser, and apps.