Hotel seeks POS system

We are a hotel in southern Germany and have 20 vacation apartments with 4 different room categories and 2 group houses. We are looking for a POS system that includes billing functions and a cash book, among other things.

We need a touchscreen and tablet (iPad) with POS software at the reception desk that are connected to the main PC.

I need a catering function, as I have to create a room number for each guest. Invoices must include a calendar for arrival and departure dates. For example: Mr. Smith arrives on January 1, 2019, and stays until January 5, 2019 - he pays additional costs on arrival and leaves a deposit. He receives a receipt or invoice showing that he has paid. This must be visible under the room number and remain open for further outstanding amounts until departure – i.e., interim payments. Upon departure, I need to see what he has paid and settle any outstanding amounts, then archive the invoice.

We have guests who either book through a travel agency. They must pay a deposit, additional costs, pet fees, etc. immediately. Guests who book through Booking.com and guests who book directly with us must make an advance payment. But not always, so large amounts are also billed. Therefore, we need the invoice with the option of paying the remaining amount.

We also offer a bread roll service, which is always billed upon departure. The cash book should be integrated and have the option of adding external purchases.

Local installation is preferred. Hotel software is not desired as it contains too many functions (e.g., occupancy plan).

One software workstation is planned. The system we are looking for should be connected to the main PC and the software would then run on the PC and tablet.