Go High Level CRM Developer / Integrator

I'm consulting a Marketing Agency that leverages Go High-Level CRM software that is white labeled for their business. All of the clients of that company are Medical Spa's who also have a separate software for Electronic Medical Records and scheduling. The clients use Aesthetic Record, Jane.app, boulevard, etc. Only Aesthetic Record has a Zapier Integration that will push all contacts in Aesthetic Record to the Hi Level CRM, but it only provides limited data and doesn't sync appointments etc. I need to develop a solution for our clients that is seamless that appear to them there is a seamless integration.