Trackpad and Keyboard not working, even after replacing the Trackpad

I have a 2017 15" MacBook Pro (A1707), and the Keyboard and Trackpad stopped working. I have replaced the Trackpad (and the flex cable) myself, as I read that a faulty one can cause both of them to become unresponsive.

I have tried (none of them worked):

• resetting the SMC, NVRAM/PRAM
• running Apple Diagnostics (no issue found)
• booting into Safe Boot
• reinstalling the latest available MacOS (Ventura 13.7.4)
• installing Windows 10 with Boot Camp drivers

What I noticed:

• The Keyboard is completely unresponsive, apart from the Option-Command-P-R combination, so I assume that the computer knows what kind of buttons are pressed, just ignores it.
• The Keyboard backlight is gone too, it's like if they didn't even receive power, which is not true.
• Both the original Trackpad and the Trackpad flex cable were fully functional, because when I tried booting the Mac with the Trackpad disconnected, the fans started to spin very loudly and the computer was slow as well. I have read that the Trackpad has in-built temperature sensors, which when removed, causes the computer to think that it's overheating as it is unable to read the data from it. So I can safely assume that the original Trackpad was functional, just unresponsive, but I replaced it and the flex cable anyway with a genuine part.
• Haptic Feedback is missing as well.
• Computer is usable with external keyboard and mouse attached to it.
• Touch Bar works just fine.