One great option is to use the blockstream satellite feed: it's available most of the world and has no ongoing cost.
If I am not mistaken, this has the same issue as any other centralized ISP as you are trusting the operator of the satellite, blockstream, to provide accurate data, as it is in control of the satellite.
But there is a useful thing you can do-- have a diverse network connection.
Having multiple connections to the internet will help you detect any tampering with the information being sent to you. If you can establish a connection to a server you control located in a different country to connect to the internet as an additional means to connect to the internet, you can become increasingly sure you are receiving untampered information. It should be easier to establish a secure connection that any malicious ISP would have no interest in interfering with.