Need to Understand the Hardware (Serial) Failover Vs Network Failover in F5 - LTM v11.3?

The features require a network connection between the devices, if that can be a non-failover connection, I do not know.

Going back to the first link I posted, which was updated last month, hardware failover is still recomended due to faster response times. Under that where it mentions certain features need a network connection, it states failover mirroring, which I believe are the features described in the second link I sent.

Beyond that, I do not have any information. I went through this same conversation last year when for the first time I had BigIPs close enough together to use the hardware failover. Due to the fact I had been using network failover for many years, and that some hardware lacks the serial port to handle hardware failover, my account team and I decided my best choice was to stay with network failover.

Given your situation is the exact opposite of mine, I would question whoever made the recomendation for you to switch to network and ask them why.