In Visual Sutdio 2019, Angular+ .net core identity is nearly done by a single click. But that is not easy if you wish to add extra custom claims. I have tried to used IdentityResource or IProfileService to config the Identity server at Startup.cs. That is not successful. That is easier to build own in this case. Mainly, you need to build login service by yourself.
At this stage, I believe the angular code can be reuse. I just need to config it to use my own login url.