You have multiple VPC networks (in separate projects) that need dynamic route exchange with on‑prem. Can a single Cloud Router be attached to multiple VPC networks to serve them all?

A Cloud Router is a regional resource and is always associated with a single Virtual Private Cloud (VPC) network. Therefore, to enable dynamic route exchange with on-premises networks for multiple VPC networks, you must deploy a separate Cloud Router for each VPC network that requires this functionality. This applies even if the VPC networks are in the same project or different projects. The option stating one Cloud Router can attach to many VPC networks is incorrect because of this one-to-one association. The option about a host project router automatically serving service projects is also incorrect; while Shared VPC allows service projects to use the host project's network, each VPC still requires its own Cloud Router for external dynamic routing. Cloud Routers are not deprecated, and Cloud NAT serves a different purpose (network address translation) than dynamic route exchange.