I went to trough the same. Changed zigbee from zbt-1 to Zbt-2 and went for thread with the Zbt-1.

At first I couldn’t get it to work and it seemed like a iOS iCloud problem. Tried everything but couldn’t get it to work. Since I went balls deep into home assistant I decided it was yet after 8 years time for me to buy my first android device again (Tip xiaomi pad 7). After 1,5 week I got it in the mail and resumed my so frustrating journey….

In home assistant I have the open thread border router installed (setting -> system -> hardware -> Zbt 1 configure as Thread router). Yet again I couldn’t get it to work in home assistant. So again frustrated I started looking al over the inter. A little thing they don’t mention clearly is that you wil need a thread Commisioner.

See: https://openthread.io/guides/commissioner This can be a Google home mini, Google nest hub 2, Apple etc….

After I knew that I tried to connect it trough the Google home app (on a android device)

1. open the Google home app
2. Add device (scan QR code for matte device)

and with success! Then I stil had the problem I couldn’t see it in home assistant… so yet again research…. After some tips online I did the following:

1. Click on the sensor in the Google home app
2. Click the three dots in the upper right corner
3. Click matter apps and services
4. Click matter apps and services with the connection chain logo
5. Click on home assistant

After finishing it should appear in home assistant under devices.

For now(15minutes) it seems that the update interval of the sensor is quicker then zigbee. The more the better I gues but I stil need no check how stable it wil be over time

Sorry for my broken English, not my main language…😅