Paul is a member of the legislative branch, and has no legal authority to arrest anyone. The absolute most he can do is send a formal criminal referral to the Department of Justice asking them to prosecute Fauci. And he already did that way back in July. DOJ -- under Merrick Garland -- declined to arrest or prosecute Fauci.
So exactly what else are you contending that Paul should have done regarding Fauci? Paul doesn't have the authority to order the arrest of anyone., so I'm not sure what you expect. Paul did file a criminal referral on Fauci way back in