Vote for Shelly UNI

Yes. Driver is actively supported.

Looking at this line makes me wonder if you installed the whole bundle or just a single file. This driver consist of multiple libraries and some custom child devices. And input device code seem to be missing.

To install all the dependencies you have 2 choices:

  1. Install files one by one
  2. (recommended) install full bundle with all dependencies at once.

To install bundle you need to go here ge4d / hubitat-code / Bundles / Bundle1.zip — Bitbucket.
On this page you will see Text/Link 'View raw'. You can either open it (zip file will be downloaded) or copy this link.
Then on the hubitat bundles tab you need to press "Import ZIP".
Then depending on your previous step point either to the downloaded ZIP file or paste a link from 'View raw'.

You can check this post Shelly Device Handlers for Hubitat - #454 by dmitry.rozovik for images.

Let me know it you need any help or have issues)