Hi. Nice to meet you, Elektronic Expert here, you can Look at my Profile for my past project
I have read your description, I already do similar job like this, Use ATMEGA32u4 and NRF52840 (BLE), the firmware use QMK and also can use arduino programmer
but for this job, I just want to use arduino software
You can sent me a message to talk for detail, Tell Me What your Problem, and let me help you to solve it
Best regards, Alif