I'm not sure of every type of trouble folks might have using selects, but for the subset where using a hardware keyboard is required, you can usually type into a focused select just as you can type into a text input. Getting an Android/iOS on-screen keyboard to do this without a special configuration might not be a thing, I'll admit.
The only tricky part, for me, is deciding whether I should type a state abbreviation or a few letters of the full state name, which in my case differ enough to be quite annoying.
