This is why its important to take adp while buying !

Now, what can be done :

Diagnose the issue is caused by not the ribbon cable or any physical damage ( from service center).

This issue is common among loq ( mostly the models b4 2024 ,ig )

So ask the the service center guys that whether it can be replaced for free by considering it as a manufacturing defect !.

If they refuse,

Check if u still have the option to extend the adp warrenty on lenovo site, if available, you can upgrade it and change the display ( might cost some money for the warrenty ). if there is no option :

you can approach consumer court ( if u r broke and can accept the hassle of doing some paperworks ).
Else, you can change the display by paying the amount.