Possible to use T-Mobile 5G Home Internet Gateway with Dual Wan setup?

LogChain wrote:

#8c9491,

    So if I understand you, you have now gotten your T-Mobile 5G gateway, shut off its wi-fi (double NAT), and successfully setup your Asus router for dual-wan with T-Mobile primary and Xfinity secondary.  If so, have you tested the function by disconnecting T-Mobile, detecting failover to Xfinity, and then reconnecting T-Mobile to confirm fallback to T-Mobile?  Are there any "tricks" to this setup?  Gracias.

Yes, that's correct. WiFi is turned off on T-Mobile Gateway + it's connected to Asus RT-AX86U 2.5G port, Motorola cable modem for XFinity is connected to ASUS router Wan port. In Dual WAN setup T-Mobile is selected as main Wan, Xfinity as fail-over + fallback checkbox selected (using 5sec ping to google as connection check). When I disconnect T-Mobile Gateway form Asus router XFinity cable kicks in within 10sec, connecting T-Mobile Gateway back makes Asus to fallback to T-Mobile within 10sec.