In addition if this service is a problem, consider there could be a thousand providers you have never heard of providing the same kind of service but while going out of their way to make sure you don’t actually have a way to block it.

If you really ‘need’ to block that kind of connection the onus is on you, not on the services.

Absolutely. There are block lists out there that can help but they are unlikely to be perfect. This guy seems to be up to date; https://github.com/oneoffdallas/dohservers