Have read many posts and am convinced I have some type of configuration issue.  All of my new devices (e.g., iPhone XS, Surface Pro 6) seem to top out at 100/100mbps.  I don't use mesh, have 3 R500s and a ZD 1200 connected to Verizon FIOS Gigabit internet which delivers 800+mbps to my hardwired devices/PCs.  Have setup separate 2.4 and 5 networks and they all seem to max out at 100mbps.  Just seems too coincidental.  It's a private home with no interference.  Thanks