Some employees would like to have a split between business and personal calls, is that possible?

All latest eSIM smartphones are Dual SIM with both a physical card slot as well as an eSIM.
That means that an employee can activate a subscription on both SIMs. For instance, his/her professional number on the eSIM and his/her private number on the physical SIM slot. In that case the employee will be able to use 2 phone numbers at the same time on one device.