This issue had been going on for several years now, and happens in two different houses with different network systems (although the networks have the same name and password for convenience).

Both systems are made of several play 1s and several One SL, one also has an old playbase grouped with two play 1s. Some units are in pairs, some are standalone. In each house the system has at least one speaker connected via Ethernet, I kept wifi activated on the speakers. Both wifi are mesh systems with several repeaters (google mesh in one, different brand in the other).

Whenever I try to adjust the volume or change songs with the Sonos app (android or iOS, latest version at the time of writing), it works instantly when controlling One SLs but takes 10+ seconds to react with the Play 1s, making them unusable. The same issue happens when they're directly playing from the Spotify app. If I use voice command via a Google home unit, the Play 1s react immediately, which tells me there's nothing wrong with my system. I submitted several diagnostics to sonos support and they confirmed my network is fine, everything is fine. They concluded it's the app. 

Has anyone managed to fix this issue?

Can sonos fix the reactivity for the older units when controlled via the app, and work with Spotify to address the speed issue? I don't see any reason to upgrade 6 play 1s when they work flawlessly when controlled by the Google assistant.

Thanks!