I find it very intriguing you landed on 200ms, considering the default beacon rate of the majority of WiFi access points is 100ms. Clients do not like going much longer before you start dropping beacons and discoverability tanks... which is shown in your results. Genuinely fascinating.
BLE operates on a very crowded frequency. WiFi, Bluetooth, etc are all on the same frequency and spamming out thousands of packets constantly.
We had to triple our broadcast frequency and period in order to reliably detect a beacon within 5 seconds of a phone being in range.
We settled on 200ms frequency and broadcast for 15ms.
Our decide had a 10 year battery life on a couple coin batteries…