Identity Server 4 and Asp.Net Core Identity as separate services

I have used quick start tutorial 5 sample to use IS4 with Asp.Net Core Identity. It works perfectly. But, as per business need, I need to extend the core identity to a large extent and add more APIs on top (will have its own DB). I thought it is a better idea to keep the user management using Asp.Net core identity and IS4 as two separate microservices, so that they can be independently scaled up and down. How can I achieve this? Any samples/references would be really helpful.