I have a question about DNAC that needs to be consulted. There are multiple Catalyst 9500 switches in the network. They are configured through DNAC to allow multiple switches to have the same distributed gateway address (for example, the IP addresses of loopback 1000-1050 of multiple switches are the same), and these IP addresses will be Being networked into the BGP process, is it allowed in SD-Access? What does this cause? Is there a document to explain?
If DNA-C configured your fabric, then it is expected that every edge switch will be configured with the same anycast gateway IP address. That makes host mobility across the fabric really easy for clients. In general, if DNA is doing the configuration, you can be sure that it's "allowed" and supported. It's designed to remove the complexity for you.
The best documentation for the fabric is probably the CVD
or look through the latest Cisco Live presentations.