guess its carrier stuff?

I live in south korea, and YES. My friends say its a dealbreaker, although Idk the reasons.

There is free DNS resolvers on mullvad. Check it out here.

You have to be careful since these DNS resolvers are different to DNS resolver which mullvad VPN uses. If you are not using mullvad VPN, those would be fine. But if you are using mullvad VPN, consider other.

On android, I use rethinkDNS. Its pretty configurable and open-source. On windows or linux, I use mullvad dns. They have 2 free DNS resolvers(unfiltered, adblock)

I also tried to make my friends use signal or anything that respects privacy, but it was almost impossible. They were used to their platform which is instagram or discord, and they didnt want to move since they had no reason except privacy, which is not their major problem.