Streaming - Total fail (rant)

So in pre-covid days we had a different house which I had wired to support living room (big rig), family room (ADS L710’s) and outside speakers (Niles OS20). I could play the same music through all three speaker pairs for parties or just cruising thru the house/back yard. New house now, without the ability to wire multiple speakers in different rooms. Streaming seemed to be the answer. Using an Airport Express to big rig, a HomePod for the family room and a mini-Homepod for the front porch I used iPhone/Apple Music to stream to these speakers. They all worked individually.

So it’s Derby day and our first party in over a year (all double Vax attendees). I set up a couple of my favorite playlists for music. Folks arrive and I begin streaming. Within minutes the HomePod starts playing different music than what I’m playing on the phone, the mini cuts in and out, the Airport express loses ALL connection with my wi-fi, and Apple music seems to forget what playlist it’s streaming from. Needless to say, total streaming fail and no music as I can’t stay ahead of the problems. Probably lots of reasons - wifi issues ( yet I have a 200 mps plan), Apple music sucks, maybe streaming to three different targets is too much, etc. In any case, way too many problems - I guess my multi room musical experience is over. END of rant.
I hate to say "Ditto" but I will. I've had much of the same issues to the point that I had to back off for a while. Unit is nice and sounds good enough when I get it to function without trouble shooting. 

I have concluded that there are too many handshakes which have to take place between too many pieces of equipment to make it work without hiccup. As a consequence, I suspect this is why a lot of people are using paid services i.e. Qobuz  to overcome the issues with their  better implementation.

One thing that may work for me is to hook the hard drive w/ the library, to the router itself  rather than the computer. And it may be that simple. I will do this next and it may be the problem you too are having. Better still is to get a hard drive that can be used directly to a streamer. But that is more $$$ but may be worth it because it takes away at least one hand shake from the process. Anyway, I feel your pain but I'm not one to give up .....yet

I am curious why you mentioned double vax. FWIW I didn't take the Vax but I don't take flu shots either. No anti vax but stayed more sick w/vax than w/o. And considering the various strains which are now in play, will it even be worthwhile. You have to get a new vax every year for the flu due to the different strains  
Like your Double Vax comment. 
LOL. False sense of security. BTW I am vaccinated and did spend a month in India. Very scary. 
If your friends are like mine, they would stream from their phone and jack around with me all night. 
15 plus years with SONOS….never had any issues. I have 11 SONOS speakers including 2 surround bars and 3 subwoofers throughout my home. Great app interface with many streaming partners and radio stations to choose from and equally adept at playing different music in each zone. 
I used to run airplay and it drove from fkn nuts.  Have not used it in years and my life is better for it.  Had a friend who had some problems and I told him to can the airplay and he did and he thanked me.  Sonos is a good suggestion for simple strait forward and reliable although there nodes don't have a good a rep for SQ.  Lots of other options as well like Bluesound
Agree with fuzztone.  I had Bluesound units, they did well until the individual units would commit hari kari during updates.  Tried replacing the Bluesound boombox in the kitchen with the Home Pod (well, it was on the cover of Stereophile, and I have an Apple TV in the family room that it used to sync with until Apple in its infinite wisdom changed the interface on ATV so now they are divorced) and Apples voice recognition is a bad joke.  Siri is a rebellious little girl as well, playing any damn thing she wants no matter what she was programmed to play.
  Sonos probably is the way to go for whole home Audio.  I no longer about that end point