> This is most noticeable in open source contributions. Sometimes I'll get a pull request with like 2 lines of change and 120 lines of some reformating tool.

This wouldn't happen nearly as much if you had a defined set of formatting rules plugged into CI instead of chaos

If the rule is not enforced in ci it isn't a rule. I've made that a mantra for a long time now and it helps. For a while I did verify formatting in ci but eventually we decided that formatiing wasn't as important as getting builds done fast. We still run other test and linters in ci and if they break fix the build but formatting isn't really that imbortant so we don't care. Yes our formatting is somewhat a mess but it isn't really that bad even after a decade of agreeing not to care.