Bluetooth not found for commissioning on Ubuntu LTS 24.04

I have (snap) openthread-border-router installed and python-matter-server on an Unbuntu 24.04 raspberry-pi.

When I try to discover a thread device I cannot find any, and when I try to commission (as shown below) I get an error message the bluetooth is unavailable. /dev/ttyACM0 is my bluetooth dongle and it seems that OTBR runs ok.

Some more details:

I have OTBR snap connected with firewall-control,raw-usb,network-control,bluetooth-control,bluez, and avahi-control. I have configured the OTBR and set_dataset(…) with the matter controller. I am trying to commission a thread device onto my fabric. When I discover, I find no devices and (probably most importantly) when I try to commission_with_code I get an error message indicating bluetooth is unavailable.

2024-12-25 10:20:48,358 - matter_server.server.client_handler - INFO - [281472466202080] matter wsock msg: WSMessage(type=<WSMsgType.TEXT: 1>, data='{\n  "message_id": "e1549795b2e04cb2b3b2a2336fba48af",\n  "command": "commission_with_code",\n  "args": {\n    "code": "03560539777",\n    "network_only": false\n  }\n}', extra='')
2024-12-25 10:20:48,363 - matter_server.server.client_handler - ERROR - [281472466202080] Error while handling: commission_with_code: Bluetooth commissioning is not available.

fwiw I also did the following (which I dont fully understand):

sudo sysctl -w net.ipv6.conf.wlan0.accept_ra=1
sudo sysctl -w net.ipv6.conf.wlan0.accept_ra_rt_info_max_plen=64

Most of my other python-matter-server operations are working and I can talk with a network (ie not thread) matter device.

My question is where might I look next to get the bluetooth thread operations working?

thanks much

I suspect that I am struggling because I did not pass a bluetooth_adapter_id to MatterServer.

lsusb returns:
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 002: ID 0424:9514 Microchip Technology, Inc. (formerly SMSC) SMC9514 Hub
Bus 001 Device 003: ID 0424:ec00 Microchip Technology, Inc. (formerly SMSC) SMSC9512/9514 Fast Ethernet Adapter
Bus 001 Device 004: ID 258a:0001 SINO WEALTH USB KEYBOARD
Bus 001 Device 005: ID 2188:0ae1 No brand USB OPTICAL MOUSE
Bus 001 Device 006: ID 1915:cafe Nordic Semiconductor ASA nRF528xx OpenThread Device

Does this mean that 6 should be the bluetooth_adapter_id for the MatterServer?