This week I rewrote the entirety of the BLE code such that each key peripheral device “daisy chains” off the previous one, forwarding the values of each key to the central controller. However, I was unable to get this fully working as I had to solve a few issues with getting ArduinoBLE to make a device act both as a central and a peripheral. The current code can be found here: bojuns/FP-Key-A_BLE (github.com)
Still, however, I believe my progress is on track since after some more debugging, I believe I should be able to get multiple connections working before the end of next week.
Next week I hope to finish the daisy chaining protocol and test it for latency measurements.