iPhone X has a green line on the screen. What is damaged?

After dropping my iPhone X, green lines appeared on the screen (attached image). Searching for the problem online I could not find a satisfying answer. I would like to know if this is clearly a display (or display cable) issue, or if it might be a graphic driver/chip problem; E.g., Can I solve the problem with "simply" replacing the display.

I am assuming that there is no guaranteed answer to this, however, any best guess or with high probability answer would help me deciding the fate of my phone :)

NOTE I did a repair myself, solution added as separate answer.

It looks like a hardware issue, display or cable hard to tell, but I'd guess display itself.

A quick test to make sure it's not earlier in the structure is take a screenshot & look at it on another machine, phone, pad, computer. The line won't be there in the screenshot if it's a hardware fail after the GPU.

In my experience, as a former Apple Authorised Service Provider, this issue often appears together with multi-touch issues on the iPhone X and comes down to the display unit. There is a repair program for iPhone X devices with touch issues.

I'd suggest a visit to the Apple Store or an Apple Authorised Service Provider and see if they can perform the repair under the program or otherwise perhaps wait a little bit until the issue occurs (again, in my experience, it most likely will do so, if only intermittently) and get it replaced then.

Opinion: I'd advise against replacing the display yourself on an iPhone X (or any (splash-) waterproof iPhone for that matter) unless you really know what you're doing since not only is opening it a pain, but so is resealing it properly. Apart from the fact that it's very hard to get decent replacement parts.