Audio buzz in Adobe Premiere Pro & some websites on my MacBook Pro

I am getting a pronounced audio buzzing through my external speakers when I click into the Premiere Pro window. When I click out of that window (back to say, the desktop) the buzzing stops. This can also happen-- but not always-- in web browsers like Chrome, but not in all tabs. For example, if I'm on a website like Google, then click into another tab for the YouTube homepage, the buzzing starts up. (And YouTube isn't even playing a video, just the act of clicking into the tab starts the buzzing.)

I don't hear the buzzing from the internal speakers.

My machine is a 13-inch M-1 2020 MacBook Pro running Sequoia 15.4.1.

Thanks!

[Re-Titled by Moderator]