So I installed my Deco M5 a couple weeks ago. Set it up as a router connected to my ISP modem running 1Gbps internet. Everything going fine. Was getting between 400 and 100mbs on wifi around the house and 500mbps hardwired to my PC from the deco main unit.

A couple days ago the wifi was consistently rating at 19mbps regardless of where I was in the house.  Tried it on the and was getting identical speed readings.

I reset ever device in the mesh and it fixed the issue for about a day. And now I'm back to the same issue..... Not sure what to do here.