Never mind - the Homey Community Store has an old version of the NUKI Direct app listed (v3.0.6 from nov 2020) without NUKI Pro 3.0 support. Sideloading the latest version of the app directly (v3.1.1 from aug 2022) through CLI makes it work like a charm.
For future reference a quick step-by-step on how to sideload the app:
- Download and install latest Node.js (link)
- Download and unpack nuki.homey repository (link)
- Start node.js command prompt (in start menu)
- Install homey packages by executing command: npm i -g homey
- Login to Homey by executing command: homey login
- Go to the location of the unpacked nuki.homey repository (see step 2)
- Install the nuki.homey repository by executing command: homey app install
