Im using my travel Router with nordvpn and with mullvad and i get horrible intenetspeeds without knowing the reasoning.
My internet connection in my travel country is around 110 mbits (mobile Network and i connect to it via repeater mode) and connecting via mullvad wireguard or nordvpn openvpn results both in internetspeeds under 1 mbits!!
Also my zerotier home Router solution doesnt work properly with horrible internetspeeds, but i dont care right now if the other workarounds would work.
Let me summarize how I see your environment
(A) localMobileNetwork <-bridgMode-- (B) AXT1800 --wifi-- (C) yourDevice
When you have no VPN configured in (B), your measure internet speed ~110 mbit.
When you configure either nordvpn OR mullvad on (B), the speed measured on (C) is down to 1mbit.
Can you please:
check the CPU usage if your AXT1800 in both situations (VPN configured and disabled).
You can use top or htop for this.
with no CPN configured on (B) - can you try to use any of the VPNs on (C) and measure your internetspeed?
The idea of the 1st test is to see if you hit any (CPU) capacity limit on your AXT1800.
The idea of the 2nd test is to check if the VPN speed behaves similar without changing your AXT1800.