Buttons not working Pi Zero 2 w

[Drippydh]

Thank you for the great work! I ordered all the parts and put it together using a Raspberry Pi Zero 2 w.
I was able to figure out a lot by myself, but i'm struggling with the buttons. Hope somebody can help me out.
The issue:
I got a couple of buttons that are not working/getting recognized. The buttons DOWN, RIGHT, B, START, LEFT TRIGGER, RIGHT TRIGGER and the LIGHT BUTTON are not getting recognized.
Steps I took to troubleshoot this:

1. I tried the troubleshooting with a multimeter to test the continuity and that's all fine.
2. Soldered new buttons in place (no luck)
3. Test continuity again, all buttons get positive feedback but no luck in retropie
4. Desoldered the Pi and soldered it on a new PCB with new buttons (samen result; same buttons that didn't work)
5. Test continuity again and this was positive, but no luck in retropie

Because the exact same buttons didn't work, I'm wondering if this is maybe a software problem?
Anybody that can point me in the right direction?