There is nothing out-of-the-box to do that.
I have a customer who does what you are describing, and much more. They built their own provisioning application which does everything using API calls to Genesys Cloud.
There is a User Templates app in AppFoundry which does some of it (but not the custom fields):
https://appfoundry.genesys.com/filter/genesyscloud/listing/82afc319-fa67-4519-9a2b-30e0ae551a3e
There might be another add-on in AppFoundry that I didn't see right off.
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George Ganahl GCP (Genesys Cloud)
Principal PS Consultant
Genesys
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