How can I switch keyboards using gesture navigation only(no navigation bar)? (OnePlus 5t)
Some keyboards may provide such features. E.g., Gboard allows you to hold the spacebar to bring up different languages and input methods. I've tried some Chinese keyboards as well, but I don't remember any implementing this feature, as they prefer to lock you into their own keyboard. So, for now, I guess you have a few options:


Stick to one keyboard that offers all languages and features you would like to use (hardest),
Find keyboards that implement keyboard-switching shortcuts,
Use a more customizable gesture navigation system that allows you to associate some gesture with keyboard switching instead of the built-in one, or
Live with the current situation.