If we create new Services, and do not want to use ITPAM for these new Services, rather we set the Approval Process to use the "Policy driven approval process," would there be any issue arising for having both Approval processes running/enabled at the same time or is it one or the other?
If your service is defined as "Policy Driven approval process " type , then : when a request is raised to this service , it will search the policies you defined in your catalog system and find the matching one , and then assign the pending approval task to the person based on that matching policy's definition . If you service is defined as "Workflow Driven approval process" type , then when a request is raised to this specific service , it will kick off the specific PAM approval process based on your event-rule-action definition and that PAM approval process will do the pending approval task assignment accordingly . So how the request is assigned for pending approval is based on the service's approval process type . They are not conflicting each other. You can have some services defined to use policy driven , and some services defined to use workflow driven .
Policy driven approval process is only for assigning pending approval task