[ciguy]

This sounds like your router has been hacked and your default DNS set to malicious servers. I've had this happen a few times in Thailand where the default ISP routers had a vulnerability. The hacked router would set the DNS to servers controlled by the attacker, and then selectively route specific website such as banking to very good clones. Try manually setting your DNS to 8.8.8.8 and 1.1.1.1 and see what happens.

[RunawayGalaxy]

OP said that the problem was happening over 4G.

[elitistphoenix]

"all using the same provider" - could be the isp's dns server that was hacked.

[curiousgal]

Quite recently I came across a router where the DNS server was set to a Coinhive server.