I had something similar on one of my previous phone's which turned out to be an issue with the connection ribbon between the display and the internal board.
If I gently pressed on the left hand top corner the line would disappear for a while but then reappear @Shubham Samdaria
If this is the case with your phone then a hardware issue can only be fully resolved via a repair.
If your phone is past it's 2 year Manufacturers Warranty then have a look at any relevant Home Contents Insurance you may have to see if your phobe is covered or some Bank Accounts provide cover as a perk of the Account or pay the repair fee Samsung will be asking for.
Or a last resort could be to upgrade to a new phone.
The Samsung Team here or the Samsung Support Team for your region wouldn't be able to circumvent the decision of the Samsung Service Centre.
If I can be of any further help then please don't hesitate. Take care. 😎
Daily Driver > Samsung Galaxy s²³ Ultra 512Gb in Phantom Black.
The advice I offer is my own and does not represent Samsung’s position.
I'm here to help. " This is the way. "
