I am planning to move from GitLab to GitHub and just started to experiment with GH Actions.
One thing I see is that I have to indicate that I want to run on a self-hosted runner for each job.
Is there a way to set a default for the Organization, or have it defined only once in the workflow YAML file?
I don't believe so. This is just another attribute that you need to consider when specifying a place for a job to run. For example, you already need to specify what type of system (e.g., OS and version) you want to use for each job via the runs-on directive, since there's no reasonable way to guess, so specifying self-hosted instead isn't exceptionally burdensome.
