For privacy aware people it can be important that an open source and well trusted extension is available.

I thought the whole point of iOS and macOS content blockers is that it does not have to be trusted, since there is never any data flowing out, only a list of blocked IP addresses that the operating system refers to (like a windows hosts (file).

It's been possible for about a decade to use Firefox Focus as a Content Blocker for Safari. I assume it's open source, "well trusted" is of course subjective.