macOS Bluetooth very high retransmission rate
Super graphs and presentation of this item - you are correct to be concerned if you are getting the feeling that efficiency is low right where the Mac is.

Couple things to help set conditions. You will want to track what exactly is plugged in physically to the mac. Everything from which cable - which port - as you make screen shots of times with high retransmission, you will know how often that happens and if it’s only when one cable or one device is attached. (And you will have to detach devices - split-half troubleshooting if needed or one by one)

Make note of devices that generate interference even when they are properly working:


https://support.apple.com/en-us/HT201163 - About USB on Mac computers
https://support.apple.com/en-us/HT201542 - Resolve Wi-Fi and Bluetooth issues caused by wireless interference


Hopefully you don’t need to capture the Bluetooth traffic to understand the spikes and cause of retransmission - there are devices that can do this but it’s kind of technical and the good tools cost money and time to learn. If the only problem is the Mac, that’s a good reason to think it’s part of the issue either causing interference or more sensitive to the interference than your same iOS devices and headset.