Does the touchpad show up under dmesg?
Have you tried it from Xorg or another non-KDE desktop? Iirc Touchpads only show under Plasma 6 Wayland if they’re controlled by libinput. I’d grab openSUSE’s 900MB LiveUSB image with Xfce, boot it, and test real quick.
I also wonder if this might be something with I2C and ACPI; forcing a Windows OSI might do something different: Fedora 40 kde battery percentage not updating/always in charge - #19 by Espionage724
Also in-case you’re using a really-new kernel: https://www.phoronix.com/news/Linux-6.12-Drops-PixArt-Driver