you can also go for the opensource version of harness and self host it https://www.drone.io/

Drone CI is open source , but the LICENSE is very tricky https://github.com/harness/drone/blob/master/LICENSE#L61-L88

ooh eww, umm I wonder if thats even a part of the apache license in general thats ya...

A drone fork: https://woodpecker-ci.org/