Wieczorek, Krystian Welcome to Microsoft Q & A Community Forum. "Microsoft.Maintenance/register/action" permission doesn't seem to exist. I am checking this with product team on this and will update the document accordingly. You would need this permission to register the Microsoft Maintenance resource provider in your subscription. Users with owner permission as well can register the resource provider. For more information, on how to register resource provider you can refer this document.
If you are not able to view resource groups, you need below permissions to create, update or read resource groups in your subscription.
- Microsoft.Resources/subscriptions/resourceGroups/write
- Microsoft.Resources/subscriptions/resourceGroups/read