Old iPhone password incorrect, cannot unlock/restore

Hello, i bought a new iphone 17 and was trying to sell my old iphone but somehow the phone password is incorrect but it has never been changed and I always had the same 4 digit password.

My old Iphone is visible on Icloud and it verifies that phone is mine but I have no idea how to unlock it. I've tried connecting to the PC, restoring but when I connect the cable, it says Unlock Iphone to use accessories which leaves me with no option to restore via PC.