HassOS and Sonoff Zigbee 3.0 Dongle Plus

If you can see it via the terminal then check if you can see it under hardware in Home Assistant OS?

Configuration → Add-ons, Backups & Supervisor → System → Host → Three-dots → Hardware

Also read the many more tips here → https://community.home-assistant.io/t/iteads-sonoff-zigbee-3-0-usb-dongle-plus-based-on-texas-instruments-cc2652p-20dbm-radio-mcu-now-sold-for-14-99/340705

Not related to your original issue but recommend also following tips here → https://github.com/home-assistant/home-assistant.io/pull/18864 as well as best practices later → https://www.home-assistant.io/integrations/zha#best-practices-to-avoid-pairingconnection-difficulties

The default firmware it ships with should work out–of-the-box but always recommend upgrade firmware