Janssen Auth Server is stateless, so you can spool up as many instances as your load requires. But as there is only one hostname, you need a way to distribute the requests. Typically, this is where a load balancer comes in. The load balancer also terminates the SSL connection, which offloads the cryptographic compute from the application. In cloud native jargon, load balancing is called HTTP Ingress.
In your load balancer configuration, you can use any routing algorithm. There is no need for "sticky sessions", or whatever the load balancer you are using calls that. For example, it's ok to use even round robin. Although modern HTTP ingress controllers enable some very flexibility routing options to do A/B testing and zero downtime updates.
As Janssen Auth Server doesn't really care what load balancer you use, some options you might want to consider are:
Amazon Elastic Load Balancing
Google Cloud Load Balancing