Some approvers are taking a long time to approve. IT service desk agents can manage this situation, because there delays response will affect ticker SLA
What @Dirk Ronsmans said.
In the SLA configuration in the Conditions section there is a "Pause counting time during..." section where you can exclude a status. If you have a discrete status which requires approval such as Waiting for Approval then just exclude it from the SLA timer so that agents don't get penalized for approvers taking too long to respond.