Did you also turn off your speakers and not restart them till the router was fully up and running, haha? It’s only by doing that you eliminate the possibility of duplicate ip addresses being the problem, haha. 
 

I just went through and did it exactly like sonos recommends and there’s still a major delay when the speakers are grouped.

You’re not telling us much. Is it a secret? Care to share what you mean by “did it exactly like I needed to”? What did you do? Comments like “I have a nice modem and mesh network” don’t tell us much. What modem? What mesh network? 

Or, option 2, I’ll pass on this and see if anyone else cares to contribute. 

When my system was laggy when the controller was first connecting and when changing volume or some other functions I couldn’t figure it out. Sent Sonos a diagnostic and they found several issues here with WiFi interference.

A diagnostic is quick, send it when you have the issue. Then call it in when you have the time to troubleshoot.

Same thing here. Since few months, i noticed a seconds delay when increasing or decreasing volume on both Play:1 in a config with playbar and sub. Called support and we were checking wifi channel conflicts, tried other channels (sonosnet), reconfiguring for 1 hour, with no success. Play:1 alone works fine... I was told to use the app, which works fine and relatively fast. I am not happy with that solution, given the immense cost these components have in comparison to competing brands.

I’m having issues adjusting the volume and skipping from one song to the next. For the volume control it takes approximately 20 tries for me to reduce or increase as the volume just readjusts itself back to its previous state within a second of me increasing or decreasing. The same applies to switching between songs, the system has a very delayed reaction time. All these issues started with the app update. I am using two Sonos Play 1’s. Is there any resolution for this?