Hello @swift-farmer-36942, so I have just done some testing and have come up with the possible solution. In my datahub instance I had 4 users that I created in my OIDC. If I clicked in their respective 3 dots (to try to reset their password), as you pointed out, such option appears grayed out.
So I invite a fictional user using a Share Invite Link. After the user putting its info and logging in, as the root user I am able to reset that user's password.