I'd like to join all of my on-premise machines to Azure AD (and remove them from the local domain). However, it is procedures such as this one that are incredibly complex to set up. I'd like to recommend that Azure engineers refine and simplify such a process as this.

https://docs.microsoft.com/en-us/windows-server/administration/hybrid-cloud-print/hybrid-cloud-print-deploy

The easier you make doing a task such as this one, the quicker folks like me will migrate users over to Azure. It should not be so difficult to implement something so basic such as accessing an on-premise printer (that's joined to a local domain) from AAD joined machine.