If you're truly using airplay, then no, you can't
there are 2 ways you can play music on the HomePod, and they look remarkably similar on the phone
You can play it on the HomePod and the music app and controls on the phone are just a remote control for that player, OR play it on the phone and then send it to the HomePod via airplay.
Because of the way apple has it set up, they look and act almost exactly the same, but one will say "iPhone -> HomePod" and the other just says "HomePod" (it will probably have the room the HomePod is in, vs the actual word)
The first way, you can still continue to play music/video on the phone
the second you can't.
The first way currently only works with Apple Music, (supposedly coming soon to others, although I think pandora is already working, Spotify defintly does not)
the second way works with anything that will make audio on the phone.