Is what Musk and DOGE are doing at Treasury illegal? Are the guardrails on US Federal power gone?

Say what Musk is doing at Treasury is illegal. Can he just expect that Trump will pardon him and/or Trump will tell the Justice Department to not investigate it as a crime? If a court issues an injunction, who enforces it?

It feels like all the guardrails are gone and the steps are really icy!!!!