The mesh network with the latest firmware has become more unstable. Sometimes looses connectivity Was expecting more from a mesh of this price range

Hi Since the latest firmware update for DECO M5, everytime I try to opimize the network, I get (very quickly) a message saying the network is optimized. Considering the all the clients that connect to

I have at home a Deco M5 (AC 1300) with the lastest firmware. After using LAB option, it says the channel is congested. How can I change to a less congested channel? Thanks