I've been following a similar path: automation and testing give me certainty and peace of mind when I'm working on bigger teams, so they should also improve my personal projects, right?
Well, the difference is that my personal projects are used only by me in limited ways, and I also don't have to worry that someone will break the build when I'm not looking. So the extra work making things super safe would not pay off that much.
Except when I feel I'm losing grip on what I'm doing, either from having to cover many use cases, not being experienced, unstable dependencies, or risk of data loss. That's when I set up CI pipelines for my personal projects.