Sure, I just want the core browser stuff and plugins, security/privacy kinda goes with that.

It feels like browsers are like old IDEs where everything is bundled in. I think it would be much better it they were more like modern code editors where people can make their own custom IDE by installing the plugins they want.

Yup, providing better APIs for external bookmarks management, password management, etc would be much better than trying to provide some “one size fits all full featured built in” implementation.