I think I hit a bug on 4.2.2 release3 (beta) on the MT3000 Beryl AX, it stops routing traffic to the internet when both the Repeater AND USB tethering are enabled.
I’ve tried to disable Multi-wan on the GUI, but it doesn’t help.
Connecting just the USB tethering device OR the Repeater works just fine.
I’ve also replicated the issue with multiple different USB tethering devices (incl. a mifi) and made sure all devices had different subnets to avoid eventual conflicts.
ps: I’m not willing to downgrade and test with older firmware, as the WIFI driver and MAC Clone were too buggy
Basic settings in my case: MAc clone enabled and set to a random address, AdGuard on, Repeater On in auto 2g/5g mode, Multi-wan priority order with Repeater first → Internet up
Connect USB modem, leave Multi-wan in Failover mode with 1st prio on Repeater → Internet up
Change Muti-wan 1st prio to Tethering → Internet down
Disable Repeater, i.e. usb modem is the only ISP → Internet up
Re-enable Repeater → Internet Down
Change Muti-wan 1st prio back to Repeater → Internet up