Thin lines all over the screen, heavy graphics issues following

I got there inside, it looks fine. Which means nothing of course

External screen works good.

So you suppose there's no other ways but to swap the panel?(

Looking fine and being fine can be very different ;-}

Electronics often involve debugging the signals digging deep into the logic and having access to the small custom SMT devices used.

Getting the needed schematics and board views are difficult to get. This is one of the mandates of the Right to Repair movement having access to them and the parts.

At this point in time getting a new display assembly is your only option moving forward. There is some logic on the main board that also effect things but that's more rare.