I wrote an article to discuss about data movement latency between AG groups:
Troubleshooting data movement latency between synchronous-commit AlwaysOn Availability Groups
Now I develop a tool to analyze AG log block movement latency between replicas and create report accordingly.
You can download it here: https://github.com/suyouquan/AGLatency/releases/download/V1.0/AGLatencyV1.01.zip
Video: https://github.com/suyouquan/AGLatency/blob/master/AGLatency.mp4
You capture log block Xevent trace from both primary and secondary replica for 5-10 minutes and then this tool will generate report about the latency of the log block movement.
Regards,
Simon