Route Server is Virtual WAN Routing-lite with BGP only option brought to Virtual Networks
Azure Route Server
https://docs.microsoft.com/en-us/azure/route-server/overview
https://journeyofthegeek.com/2021/11/11/a-deep-dive-into-azure-route-server/
Multi-region networking with Azure Route Server
https://learn.microsoft.com/en-us/azure/route-server/multiregion