C# Headless Scanner Remote Display

I need to code a headless scanner. The database and the QR-Code generation is already working. And the scanner can scan this code from the screen and return the request to a server. This screen should be replaced with a mobile phone or any other bluetooth connected display. The request to the server should get processed by a seperate API. Details to be discussed in private.

In use: C#, PostgreSQL, RabbitMQ, Raspberry Pi (to connect to the scanner and send the requests to the server)

Languages: German, Russian

Setup for work: Remote work; You connect to my computer probably. Flexible.