I’ve just checked on Raspberry Pi 3B, it worked just fine. The bluthoothd command line was not modified from original, this is the output I got:
patch@patchbox:~ $ sudo systemctl status bluetooth
● bluetooth.service - Bluetooth service
Loaded: loaded (/lib/systemd/system/bluetooth.service; enabled; vendor preset: enabled)
Active: active (running) since Tue 2021-03-23 08:37:11 GMT; 15min ago
Docs: man:bluetoothd(8)
Main PID: 528 (bluetoothd)
Status: "Running"
Tasks: 1 (limit: 2062)
CGroup: /system.slice/bluetooth.service
└─528 /usr/lib/bluetooth/bluetoothd
Mar 23 08:37:11 patchbox systemd[1]: Starting Bluetooth service...
Mar 23 08:37:11 patchbox bluetoothd[528]: Bluetooth daemon 5.50
Mar 23 08:37:11 patchbox systemd[1]: Started Bluetooth service.
Mar 23 08:37:11 patchbox bluetoothd[528]: Starting SDP server
Mar 23 08:37:11 patchbox bluetoothd[528]: Bluetooth management interface 1.18 initialized
Mar 23 08:37:11 patchbox bluetoothd[528]: Sap driver initialization failed.
Mar 23 08:37:11 patchbox bluetoothd[528]: sap-server: Operation not permitted (1)
Mar 23 08:37:11 patchbox bluetoothd[528]: Endpoint registered: sender=:1.8 path=/org/bluez/hci0/A2DP/SBC/Source/1
Mar 23 08:37:11 patchbox bluetoothd[528]: Endpoint registered: sender=:1.8 path=/org/bluez/hci0/A2DP/SBC/Source/2
Mar 23 08:37:11 patchbox bluetoothd[528]: Failed to set privacy: Rejected (0x0b)
patch@patchbox:~ $ uname -a
Linux patchbox 5.10.11-v7+ #1399 SMP Thu Jan 28 12:06:05 GMT 2021 armv7l GNU/Linux
By the way, the App must ask for location permission - did you grant that permission? If not, Bluetooth on Android won’t work. See here for why it’s required: https://blokas.io/pisound/docs/pisound-app/#why-is-the-location-permission-required