Agreed. Content blockers are also not executing js code for every resource the page tries to load: it's just the defined blocking rules that get processed.
I'm also using 1blocker. Lacking an existing site (or time to build one myself) for sharing 1blocker packages, I've started storing them here: https://bitbucket.org/stephenreay/1blocker-packages
I've been using 1Blocker which, while not free, uses the API and seems to work very well. (And can sync your block settings with the iOS.)