Similarly, HomePod 18.4.1 has rendered my one HomePod mini useless. It functions better playing music on Bluetooth only than it does on WiFi.. which makes no sense to me.. nothing would fix it but I just got it working, it only took wasting 30+ minutes per day for several days in a row to figure something out… I’m looking at an active connection to the same band on the same wifi network on my router’s app, all my issues appear in the Home app.
Here’s what worked for me.
I opened the HomePod from the home app, opened it’s settings and scrolled down to where it shows the WiFi and version info.
I kid you not, that’s all I had to do to get it to start playing.
BUT it’d just start playing whatever I last attempted to airplay and then would almost immediately stop playing as soon as I exited the settings on the home app…
I switched that HomePod to the main home hub and airplay has been working since.
Unfortunately, that takes my locks offline since the manufacturer made the questionable choose to release a Bluetooth model without thread capability.
I’m hoping it won’t get messed up again by switch the hub back to my wired atv but I’m a little scared to change any settings atm.