Data recovery, a53 circuit boards...

I own a Samsung Galaxy A53 5G that was broken during a construction project a while ago. The frame, screen, and battery are all ruined but both the mother and daughter boards are intact. I recently purchased a working A53 and swapped out both circuit boards and attached new cables. The phone powered on successfully because I felt the vibratory motor. However the screen does not light up nor does it respond to touch. I attached a mouse via OTG and was able to locate the pattern screen lock grid (the phone vibrates if the pattern is entered incorrectly). I then attached the device to a computer. The computer pinged but the phone does not appear as an available device, however it does appear in device management as MTP USB Device under portable devices. The device status displayed is This device is working propery and it is recognized as a Samsung.

I also tried all this with a new daughterboard with the same results. All this tells me that both the storage component and the CPU are in working order but something obviously isn't. So what can be done to recover the data I still have on the phone? I had some backed up but not all.

Thank you.