Try enabling and disabling the built in keyboard in the bios, just make sure you have your usb keyboard around or you'll be locked out after reboot lol.
Google: enter bios on <name of your laptop>
Then, once you're in the bios (or uefi bios same shit) built in keyboard should be under devices...
Try
Cleaning your keyboard
Restarting the PC completely (obviously)
Maybe try disabling the built in keyboard in the BIOS then re-enabling it
Sounds like your issue is sadly physically related to some shit stuck in the keyboard, if it's driver/software related a bios disable/enable should...