Slow Internet Speeds - Orbi RBK43

I installed an Orbi RBK43 WiFi system yesterday. After the initial install (via the Orbi app), i was getting internet speeds of about 1-2 mb/second. Prior to this, I was reaching 70 mb/sec with my previous router. After spending an hour with Customer Support, my speeds were back up to the 70 mb/second range. Now, today I am back at ~5 mb/second speeds. This is a bit ridiculous for the price you pay for these mesh systems. I have no confidence in Customer Support, so I figured I would reach out to the community to see what has worked for you. Below is a summary of my setup: Orbi Router placed centrally upstairs in my home. One router is 20 feet away in another upstairs room, while the other satellite is approximately 30 feet away on the main level. I have enabled Implicit Beamforming and MU-MIMO. The main unit is in Router mode. I have IPv6 disabled. Firmware has been updated to the latest V1.12.0.20. Any suggestions would be much appreciated. Thank you in advance.