you need a phone number to register a new one

So what has worked for me in the past is: Get a cheap android/ChromeOS device (or power-wash one that you’re not using any more) and ensure that there’s not a working SIM card in it. When you power it up and it goes through the first-time-user setup, it asks you for your Google account, and provides you with the option to create one if you (claim you) don’t have one. Since there’s no SIM card, the newly created Google account has no phone number attached.

I imagine that you could copy down the info about this newly-created account (after making sure it has a password and you know what it is), and then wipe/power-wash the phone/tablet/Chromebook and do the process all over again and create another Google account.

Every google-OS-running device I’ve ever owned has gotten a new Google account created for it.

Volla really needs to hire/assign some staff for their support forum The large pile of unanswered questions there does not inspire confidence in their product.

Maybe it’s better in the German-language forums.