Quest no longer works with T-Mobile Home Internet

I have a Occulus (T-mobile won't allow the use of the M*** name for some reason) Quest 2 that used to work with T-Mobile Home Internet but doesn't any longer.  Looking through this forum and other it seems to be related to the Sagemcom Fast 5688W (dark grey) router with firmware 1.102.5c.  Telephone support did not have any way to resolve, but did acknowledge a known issue with Wi-Fi clients repeatedly disconnecting from the router, which is exaclty what I'm experiencing with the Quest.  They agreed to ship me another of the exact same router but said it would have the same issue because it's a problem with the hardware.  

I don't know if anyone else has found a better workaround.  I've tried a dedicated 2.4Ghz network just for this device, a static IP, and even another router behind the T-mobile one and none of it works.