This is probably where the problem is. The snap package very likely is managed by someone else, and not by HA. So maybe there is something else or configured differently? What is the HA version you got via snap?
I would follow the official install guide instead. You have options on various supported install methods, and snap is not one of those.
And from what I read here, would recommend you:
either setup a VM hypervisor on your ubuntu, and then do HAOS install, and then passthrough USB to your HAOS VM.
or, if you are planning to dedicated the laptop to HA, maybe install HAOS directly to your laptop. This way the zigbee usb thing should be plug and play, since the driver is already there.
I did had the same issue with snap under ubuntu 22.04 install on an old machine. . And as you must have figure since snap work in sandbox mode it cannot access the sonoff dongle on /dev/tt0 . So my only choice is to REMOVE snap HA. And tthe success installation road map I followed is this:
2- Then skip the first few step and go where it says Install Home Assistant Core near the bottom of the procedure.
3- Use terminal and Install dependencies with command line provided in the text.
I had difficulty in this step because some dependencies did not install.
Checking the error message I did add the recommended package so that repeating this command worked. It might be different for you so check the error is the key.
4- Create an account
I had difficutly with the following step mainly because the groups dont exist in ubuntu 22.04 . Only need to create the three groups .
It took a while for the hass to come back. I finally realized that it was the server running accessible on http://localhost:8123. or on my local wifi as http://X.X.X.X:8123 (replace X.X.X.X with your machines’ IP address).
I plug the sonoff dungle and restarted the machine then HASS server in terminal as follow:.
sudo -u homeassistant -H -s
cd /srv/homeassistant
source bin/activate
hass
Then as explained by sonoff for the zbdongle-p here https://sonoff.tech/product-review/sonoff-zigbee-3-0-usb-dongle-plus-tutorials/ . Sonoff Zigbee 3.0 USB Dong - /dev/serial/by-id/usb-ITead_Sonoff_Zigbee_3.0_U appeared after selecting ZHA . The I selected ZNP for configuration.
The first device I added was a sonoff ZBmini switch it appeared as soon I pressed the configuration button.
The second device was a sonoff SNZB-03 motion sensor . It did not pop out. So first go to setting/integration and get the ZHA device addition. A window appears waiting for pairing. Then press the pairing mode with your sensor close to where you want to install it. So that the newly zigbee coordinator you just install find the best route to reach it.
Hope it helps
GiMiSa
Guess OP is happy with another solution. Registered here to say that you’re a scholar and a gentleman! Worked like a charm - problem was indeed with Snap. Also thanks for a very clear pointer to the install. Cheers!