You have a SharePoint admin role, you can see it listed under your account, and the SharePoint admin center still tells you access is denied. Once Microsoft Entra Privileged Identity Management, or PIM, is in the picture, this almost always comes down to the difference between being eligible for a role and actually having it active.
Eligible is not the same as active
PIM lets an organization assign admin roles as eligible rather than permanently active, meaning the role sits dormant until someone deliberately activates it for a limited window. If your SharePoint admin role was assigned this way, seeing it on your profile does not mean it is currently switched on. Go to Entra ID, then Privileged Identity Management, then My roles, and check whether SharePoint Administrator shows as eligible rather than active. If it does, select Activate, provide a justification if prompted, and wait for the activation to complete before trying the admin center again.
Give it a minute after activating
Role activation through PIM is not always instant from the perspective of every Microsoft 365 service. It is common for a freshly activated role to work immediately in some admin centers and take a few minutes to be recognized in others, including SharePoint. If you activated the role and immediately hit the same access denied error, wait a couple of minutes and try again, or sign out and back in to force the session to pick up the new activation.
If activation itself is failing
Some PIM configurations require approval from another administrator before an activation request is granted, rather than activating instantly. If your activation request is sitting in a pending state, that is expected, and the role will not be usable until it is approved.
If the role is already active and it still fails
At that point the issue is more likely a genuine role scoping problem rather than PIM itself, such as the role being scoped to a specific administrative unit that does not include the site or setting you are trying to reach. That is worth confirming with whoever manages your Entra role assignments.
If your organization is using PIM and finding the activation workflow more confusing than it should be for day to day admin work, our Azure and identity team can help you tune it properly. Get in touch if that is where you are at.