What would, for now, be the minimum set of roles/permissions required to get access to Sentinel?
I've played around with granting access as a Security Reader some additional ones (Contributor) on the Workspace, but no joy.
What permission are (minimally) required and should we apply them on the Subscription, RG, Workspace or elsewhere? Couldn't find any relevant information so far :)
You will need a subscription contributor permission to onboard. After that, you will need a contributor or reader on the RG, depending on what you want to do.
Connecting to different sources may require additional permissions, which is documented on the specific connectors pages when you connect.