It's probably easier to run your own DNS and blacklist the offending domains. There are good blacklists with millions of telemetry domains, e.g. https://github.com/hagezi/dns-blocklists.

Better yet, don't allow such spyware crap on your computer.

pfft, just don't have a computer and you'll be good

Some hobbies are more fun than others.

That is the correct way of handling this.

Everyone proclaiming a "standard" is just adding to the long list of (unofficial) alternatives.

obligatory: https://xkcd.com/927/

how is this relevant?

Not the person you are replying to, but I had the same thought come to mind. Every library and app seems to have its own way of disabling telemetry. In order for a unified way to actually result in unification, everyone has to sign onto it. Otherwise you now have DO_NOT_TRACK=1 for everyone who respects it in addition to all of the existing ways for everyone who does not respect it.