5G home internet keeps dropping

SomeoneSomewhere wrote:

I am currently troubleshooting the same issue. My set up is the trashcan connected to the WAN, fire walled, side of an Asus ac68u. The Asus is handling all LAN Wi-Fi DHCP etc. I just did a test hooking up a Roku directly to the trashcan (using the 2nd Ethernet connection) at the same time that the Asus was showing the Internet down, The Roku was able to still stream on it's wired connection.
 

My current working hypothesis is there is some incompatibility between the trashcan and a separate router (LAN side) vs the t-mobile is dropping the internet (WAN Side) my prior working hypothesis). 
 

This seems unrelated, but I wonder if there is some MTU incompatibility between the WAN side of the asus and the LAN side of the trash can. https://amithkumarg.medium.com/resolved-t-mobile-home-internet-vpn-issue-2f5ca594c23e Does not seem too easy to change the MTU on the asus though. 

Update on troubleshooting so far. Noticed that the WAN DNS on my asus was pointing at my LAN pi hole….and DHCP on ASUS was giving out itself as DNS server to clients This was working OK when with Xfininity for several months. Have changed so that ASUS DHCP is giving out the Pi Hole as the DNS server - how it should have been all along. This has also had the effect of improving the statistics from the pie hole has it now no longer shows all queries coming from the Asus router. WAN DNS server on the ASUS is now Default, meaning is getting it from the Trashcan. I also turned off the 5Hz WiFi on the asus and turn it on on the trashcan, with the theory that if I use that while working from home & VPN in to work it should be more stable. That combo seems to of worked OK, meaning I've had about 12 hours of what I think uninterrupted uptime. Not sure if fixing the DNS server, or just changing the DNS server helped.. The advice to change the DNS server came from "Nater Tater"'s you tube channel - he has a bunch of guides on the t-mo trashcan.