Help Bypassing USB Tether Restrictions

Here's my issue. I live with family that has Verizon 5G home internet, which absolutely sucks in our area. However, I have amazing service through T-Mobile. I also have a travel router, that being the GL.iNet GL-MT3000 (Beryl AX). I don't get good service in my room, which is downstairs, so I have to place my phone and the router upstairs.

I am fine using tethering or hotspot, I just want something that is going to get me past the 80gb hotspot limit.

I have tried multiple things, and I can't seem to get anything to work. I have tried the TTL trick, I have tried connecting my router to a HTTP proxy, I have tried TetherFi (which also requires a proxy), I tried a VPN (Mullvad to be specific), I just don't know what else I could try. Everything else seems outdated or like it won't work on a router. I do have Tetrd and I paid for the premium version, so if there was a way to install that onto my router (which runs on Linux OpenWRT) then that would be amazing, but I can't find a way to do that. If anyone has any ideas as to how to get around this, that would be amazing.

Some extra information: T-Mobile 5G Home Internet is not currently available in my location. If I want to use the Verizon 5G Home Internet, I get 50 Mbps on a good day, and definitely not during peak hours. During peak hours, I get maybe 10 Mbps. When using T-Mobile, I get upwards of 500 Mbps not during peak times and 200 Mbps during peak times.