Screen not waking when openning lid

Hi everyone,

I (my son actually) recently had spilled water on my macbook pro. I quickly de-assembled everything very carefully. Used Isopropanol with toothbrush to clean a part of the Motherboard + Used a ultrasonic bath to really clean it carefully and did that also with the top case + keyboard to clean the keyboard from oxidation.

I reassembled everything carefully, did a SMC reset and tada, everything was working properly. I tested every piece of hardware (bluetooth, wifi, keyboard, jack, USB-C ports, Keyboard lights, trackpad, speakers, fan, mic, etc, etc). Everything works perfectly.

If I shutdown my computer, I can restart it properly no issue.

If I restart the computer, everything works fine.

But (you were waiting for it), if I close the lid, then I can't get the screen to wake up again without resetting SMC. If I connect an external screen the login screen would appear as expected.
So I'm actually suspecting that if I open the lid (but not sure), the computer actually wakes up (unless it wakes up because I plugged an external screen... not sure).

So far I'm a bit stuck, I suspect that there is something wrong with the software or hardware piece that detects that the lid is open, but I have really no clue where that piece is to investigate.
Furthermore it seems that if I shutdown my computer normally and then close the lid (when shutdown), then I can't get the screen back (I need to do further testing to see if it actually powers up with an external screen connected, but with no external screen connected it won't cause I don't hear the booting chime).
Only solution ==> SMC reset.

So if anyone has any idea what I can test now (I did reinstall macOS, Repair Disk permission, reset NVRAM, reboot in safe mode, etc, always the same behavior so far).

If anyone has any idea what I can do next, I'd be super grateful. It's a pitty that I need to SMC reset just to get my mac to start after I close it ;)

Thank you

PS: I have a A1708/EMC 3164

EDIT 2022-07-03
Reading this thread Replace reed switch/hall effect on MacBook Pro I thought it was similar so I ran ioreg -r -k AppleClamshellState

After a normal boot, it yields "AppleClamshellState" = No

If I plug an external monitor and close the lid, if I re-run the command I get

"AppleClamshellState" = Yes

Finally if I re-open the Lid, the state AppleClamshellState stays to yes.

So Indeed I might have an issue with the hall effect sensor, but would anyone know where this sensor is on a A1708 motherboard? (or is it somewhere else?)
Thank you

I got to a repair store to ask them to repair the Motherboard. Their saying that they tested my screen with another motherboard and they could replicate the issue. They are quoting me for a full screen replacement. Very expensive.
Is it possible that the issue explained above comes from the screen itself? or some logicboard inside the screen itself?

Thank you