Working with Jenkins CasC, JobDSL and declarative pipelines, I'm not sure where the million times comes from. Sure, there are some annoying parts, and GHA has the social network for reusable actions, but apart from that it's not that different.

Oldschool maven type jobs where you type shell script into a `<textarea>`? Yeah, let's not talk about those, but we don't have a single one left anymore.

Jenkins is in every way a “Java” program, and not the good kind.

What you can say for it, is that it was free and near infinitely hackable.