I use multiple keyboards on my iOS devices English (US), Emoji, and Deutsch (German). It used to be a drag to have to click the globe icon on the keyboard multiple times to get to the keyboard you needed, but not any more. You can reach all your keyboards with just one finger!
If you are accessing a keyboard anywhere in iOS and you have multiple keyboards active you’ll see a globe shaped icon on a key to the left of the space bar. If you tap the globe once it moves to each keyboard in your list one at a time sequentially. If you tap and hold it instead you’ll get a pop-up list of keyboards you’ve activated in one view. Tap the one you want from the list and jump to it immediately. It’s fast and easy. Highly recommend for people using more than just one or two keyboards.