Not an answer per se, but just to say that I have the same or a similar issue I think, and I am fairly sure as to the cause of it: water damage, accidentally spilt a drink (a slightly sticky one) on the screen (just 50 mls or so) and despite attempting to clean it up via wiping with a damp cloth, then a dry one (or possibly tissue paper I was half asleep at the time which is actually why this happened as I (am guessing I) moved in my sleep, tipping the glass over and onto the machine, which woke me up enough to more or less try to salvage the situation as best I could in a semi-conscious sleep state) this wasn't enough to prevent damage from occurring at all.
I've had a previous MacBook completely fried by water damage so it is something of a consolation that this nearly brand new machine wasn't more affected.
Having said that it did have a screen and keyboard protector so how this still happened despite countermeasures to the contrary is somewhat puzzling to me not to mention frustrating as that is partially the very purpose of these accessories and why I bought and applied them in the first place.
I have heard that rice, if applied quickly enough, can rescue many devices from water damage or at least the worst effects of it, unfortunately it seems as though I fell back asleep before I had a chance to enact this measure given how tired I was, but seeing as though the actual bespoke defences (plastic screen protector and keyboard cover) were not enough to fully mitigate all damage I have doubts as to whether rice would have made much, if any, difference in this instance. I did pour it over the laptop when I woke up a few hours later but seemingly, at least the bulk of the damage had been done by then.
Still though, I wouldn't say don't bother with it, just because it didn't work here, hours had passed. it's best applied immediately in cases of contact with water and that goes for electronic appliances in general as it soaks up water and is small enough to get into the more unreachably minuscule nooks and crannies.
So I don't require your thanks, seeing as this is not an answer and also I wouldn't take the word of who or whatever wrote that message above this answer box anyway, there is no way of knowing if even a person wrote it for one thing it could be ai-generated text which wouldn't surprise me given the absolute superabundance and near-omnipresence of ai these days particularly in the internet sphere, (something, I would add, that if not reined in double-time may well in fact spell our eventual doom; yes, seriously) and regardless, it presumes to speak on your behalf, without, almost certainly, your consent or even knowledge... I am just contributing my experience so that you are further armed with the knowledge of what may have happened to your machine.
Unless you are confident enough in your laptop repair skills to replace the screen I personally would be reticent to undertake something as delicate as what is required here which looks like, for all intents and purposes, an entire screen replacement. Take it to the Genius Bar friend and have them
a) confirm it is water damage, just in case
b) replace the screen as necessary. It is really a shame as my previously pristine laptop now gets annoying to look at from time to time.
So a screen replacement really is necessary (in my opinion), unless the weird colouring and super-off contrast and brightness don't bother you that much. it's not a problem that's likely to fix itself though I should think