have you tried Dana lock or Okidokeys? Both have European versions. I have both of these locks but the US version.
I use VirtualKEY [link removed] software to manage both these locks. It is also integrated with Airbnb, HomeAway, VRBO etc. The reservations are synced automatically and lock is programmed for the guest and house-keeper automatically. You don't have to manually generate digital keys using the lock app. It saves you time and keeps things stress-free. I don't like to be worried about remembering to create codes and send emails to guests.
I also like one more feature that VirtualKEY Software provides. You can automate emails you want to send to guests like arrival instructions, request a review, guide book etc. I don't like to be worried about remembering to create codes and send emails to guests. I started offering instant booking after switching to VirtualKEY.