F5 BigIp cluster active/stanby in Azure, failover very slow

HA works completely different in cloud environments due to abstraction of L2 networking. Instead, I would just run a few active BIG-IP instances and load balance via DNS. More specifically, I would use terraform or ansible or some other automation framework to auto-build my cloud BIG-IP instances based off some github managed master configuration. Then I would use cloud native automation tools to manage the DNS entries. Sadly, there is no way to minimize HA failover delay in the cloud.... you are trying to fit a square peg into a triangle hole. F5 HA was designed for connected and local traditional L2 network designs. You dont have that with cloud so trying to replicate similar functionality is really a hack. Go active w/ DNS based failover.

A BETTER way, would be to look into F5 Distributed Cloud for HTTP/S workloads.