Hello,
On the BBBlue and other wifi enabled BBB variants w/ the newer kernels and images, I saw somewhere on this forum that /etc/wpa_supplicant/wpa_suppliment-wlan0.conf should get wifi working.
I am not sure exactly what image and kernel you are using.
If you would like to provide that info, okay. If not, you can always try that file.
Seth
P.S. I know that connmanctl used to work w/ kernels 4.19.x and prior but that beagleboard persons chose to use networkd w/ the more updated kernels: Debian 11.x (Bullseye) - Monthly Snapshots