The One, then the Era 100.

Since the Play 1 has no microphone, I’d say it’s most direct successor is the One SL.

But why upgrade speakers that are still fully supported by Sonos?

Not sure how you are using the speakers now, but when they are used for anything else than surround duty, I’d take a look at the Five’s. For surrounds, I’d take a look at the Atmos capable Era 300’s, provided you own an Arc or Beam (gen 2), that are also Atmos capable.

I’d not upgrade to a One or One SL, I have both Play Ones and One SLs and I really have to pay attention to hear any difference in a quiet room. As surrounds I can’t really tell, even in Full Mode.

Even an Era 100 is going to be a small, but more noticeable upgrade if used for music, less so as Surrounds.

As suggested above 300s for surrounds if your Beam is Atmos compatible.

For non-surrounds Fives would be very nice but maybe a mini-Sub would add enough to your current speakers (if not surrounds) to be worth the cost.

If they are surrounds the mini-Sub or full Sub will add a lot to your Beam Room’s sound and might be your best option.