I recently came across the issue that I wanted to setup Unifi Talk but I didn't want to buy a talk device just to set it up (this was the recommended way from Unifi)
For Unifi Talk 4.2.4 its a little more difficult but still possible:
- Go to your Unifi Talk setup page and press right mouse button -> Inspect
- Go to Network tab in Dev Tools
- Search for index-
- Reload the page
- On the new item that just popped up right click and select "Override content"
- It wants you to select a folder so select a empty folder on your pc
- In the file editor hit Ctrl + F
- Search for
internalToolingEnabled: !1 - Replace it with
internalToolingEnabled: 1 - Reload the page
Now you should be able to press the next button even with no devices!
So I began investigating the code and found out that if you press 10 times on the "Setup Device(s)" text you'll be able to skip the device step.

"you press 10 times on the "Setup Device(s)" you'll be able to skip the device step."