Slow WiFi but fast wired

I’m having a hard time figuring out the problem. I have Xfinity gigabit internet in bridge mode directly connected to my gateway eero pro 6. This is connected to a switch tp link sg108 that goes to a few devices. There are 3 other eero pro 6 hubs around the house (4200 sqft). I previously connected them via MOCA 2.5 but stopped this while troubleshooting so they are all connected wirelessly. I had a Sonos directly connected to the gateway switch but unplugged all my Sonos also in an attempt to troubleshoot. 
 

my issue is wifi (mostly in my living room) starts up on Speedtest and goes up to 20-30 before slowing down to less than 1-5 mbps. I checked speeds via a hardwired computer to the individual hubs and I’m getting great speeds. It’s just the wifi that keeps crapping out. Every now and then it’s great and I’m getting 100 plus but so often it’s weak and causes buffering. 
 

I also tried to swap out my gateway with one of the other hubs and I’m still getting the same problem.

Any ideas?