Consumer product with touch screen

Dear team,
We are looking to create Consumer products, with several inputs like USBs, DB9, etc, and controlled via a 7’ to 10’ touchscreen.

We are looking for the best cost-effective solution for Hardware and Software. The solution needs to basically power on and work, with minimum user interactions except to see information and control some hardware, a little like an advanced coffee machine. We would also perhaps like to have the device connect to a person’s mobile Phone to be controlled and to as well play music for example. Could anyone give some advice?

We have been looking at Qt but it looks expensive as we are just a startup. LVGL but I couldn’t see if you can connect a mobile device to it. Hardware NXP, Rasberry Pi, Arduino, etc… Custom

thanks in advance for any advice!