Any mailbox on lit hold in ExO requires at least a p2 or online archive license
https://learn.microsoft.com/en-us/microsoft-365/compliance/create-a-litigation-hold?view=o365-worldwide#assign-an-exchange-online-plan-2-license
If you are removing the lit hold, then the mailbox only needs a P1 at minimum, so you would only need to license your admin account with a P2 to remove the lit hold.