With teamcity you write xml for your pipeline, and you can write kotlin scripts to generate your pipelines (which just compiles to the xml above).

It's really, really limiting, and very hard to do things like "run this pipeline if on this branch"

oh god, please, no. :)

I mean, go for it if you want but I'm not sure why you'd need to maintain so many heterogeous pipelines that would warrant a tool like this.