Thanks for the clarification.
In this case, since you already performed a full cloud reset with file deletion, you can rule out software issues. The problem is most likely with the laptop's keyboard hardware. Even after cleaning, the simultaneous random activation of modifier keys strongly suggests physical damage or a faulty keyboard controller.
I suggest that you take the laptop to a trusted technician. They can test the keyboard circuitry and replace the keyboard if necessary.
Feel free to ask back any questions.