IPv6 routing with internet source from T-Mobile IPv6 only

Hello everyone,

I’m new to OpenWRT and running in to a problem I hope someone could guide me to the right direction.

I have a modem that running openwrt. It is a dual modem with a 4G and 5G modem. When I plugged my sim to the 4G slot it can acquired ipv4 so everything is good there but when I use the same sim to the 5G slot it only connect to the n25 band of T-Mobile which only provide ipv6. The router set up for ipv6 and when my computer connected it got ipv6 address from the router but I can’t seem to connect to the internet. When I ping ipv6 google address it ping successfully, both from my router and my PC. The setting I used was from openwrt and from a person on YouTube.

May I ask what could I’m doing wrong that I can ping only ipv6 address but not the internet? Is there something that I’m missing ?

I don’t know what setting to attach. If you need anything from my setting please let me know I’ll attach them. Thank you so much for your help