Airport Express A1392s suddenly not working for AirPlay

For years I have been using speakers connected two Airport Express A1392s in my living room to stream music from my iPhone or to act as wireless speakers with my TV. They have been great Airplay2 receivers.

This has recently stopped working. My phone or TV will connect to the speakers, and I will receive literally 1 second of very clear audio, and then the audio will cut out completely. The phone or Apple TV will still think they are connected to the speaker, but I hear nothing.

Four weeks ago, I updated my home wifi system to TP-Link Deco Mesh AC1900 WiFi System (Deco S4). Everything was working fine for a few weeks until this week.

I can't figure out the problem but have done a lot of restarting of phones, TVs, airport expresses and other devices, and changing settings on my Deco.

Here is what is still working in my setup: I can stream Airplay audio from any device to one of my two Apple TVs or to one of three HomePod minis in the house, so the issues is specific to the A1392s.

Any ideas for how to fix the audio dropping out of the A1392s? I can hardwire one set of speakers to the TV if needed, but then I would have to turn on the Apple TV to stream audio, and I would prefer not to have that screen on all the time. I also would lose the second set of speakers in my setup.