As of Sep 28, 2020, Sonos One, One SL, Five and Sub (Gen 3) can now stream via 5GHz and 802.11a/n wifi networks. I only realised this via router maintenance app (TP-LINK
Sonos — HifiHut
Sonos One (Gen. 2) will last longer than the Symfonisk according to Sonos Support : r/sonos