Thank you for the tips! There is an alternative way to use OGS that has been made available recently:
The workflow covers points (2), (3), (5) as everything is packed in a container (OGS can be used via Jupyter, no need to worry about Python, and execution is enabled via ogs6py). And even, with some additional steps, maybe GMSH and meshio could be integrated in the container.
For some setup guidance in Windows we used this recently.