The FlexiCapture User's Guide suggests using an NLB cluster to build a fault-tolerant configuration for an application server.
Is it ok to use an external load balancer instead of NLB for load balancing?
FlexiCapture can work with any load balancer, the main requirement is that the session should be remain assigned to the node with which the connection was made (support for Sticky Session, Persistent Session, Affinity).
For example, it is possible to configure the work of the balancer in Azure.
Important: The Load Balancer must have access to the internal network interfaces of the application server and support Windows authentication.