Prevent notifications on phone while Airplaying slideshow to AppleTV

Hi there, is there a way to turn off notifications for all apps while Airplaying my phone's screen? I'm presenting a slideshow using my phone to an AppleTV and I'd rather not go through every app and turn off its notifications (I have the 256GB model phone, it's got a lot of apps!). Do Not Disturb Mode might work (and I will turn it on), but Apple's information page that mode only turns off notifications while the screen is locked -- obviously that doesn't work if I'm trying to present a slideshow from my phone! The other thing I might try is turning on Airplane mode, but I'm trying to avoid that since I'm streaming music from Youtube Music in the background for the slideshow (this might actually work because I think I can download the music for playback offline). Still won't stop local-only notifications...