You're welcome.
There's 2 "generations" of the PLAY:5. All other devices have taken on new names. The difference(s) between the PLAY:5 gen 1 and gen 2 are a change in buttons, an update to the wifi to 2 channels, 2.4Ghz and 5Ghz so that they can be used as surround speakers, and a general look update. Probably other internal changes that can't be seen.Oh, and a microphone which has never been enabled, as it's not a near field array mic set.
The PLAY:1 also has one generation. There's a parallel release that is called a Sonos One, which also has the same new buttons, a microphone array which allows it to function as an interface to Amazon, and slightly changed exterior, although the form factor looks the same, which causes a lot of people to think it's the same as the PLAY:1, which it isn't. Both the PLAY:5 gen 2 and the Sonos One can be used as AirPlay 2 targets.
Bruce