You can ask your Customer Success manager at Marketo to help with this transition.
You may not need to take everything over, discuss what is working and what is not to determine what time and resources needed to rebuild any programs etc.
You can see if a data copy can be performed to a new workspace.
Example:
We wanted to split our Corp form Consumer team from our instance of Marketo. We got a new instance and requested a complete data copy of everything. This process took over all programs, flows, data etc. Then we could delete what we did not want and reactivite the programs we wanted. (The copy process by default turns off all activities, need to go through one by one to turn back on.)