After some tampering with the actual queue in scheduler0.staging (cleaning that up, it's staging so fine).
And limiting the number to less than 10k (100 is enough, way less workers).
We now have some github origins properly scheduled with their lister_name=github and lister_instance_name=github.
This now results in extrinsic metadata being fetched for those origins [1] (without me having to trigger the swh loader run cli).

So status on this, the git loader queue is quite filled in.
So triggering specific loading for github origins through the cli [1] was in order.
We do obtain results after that [2]