We do know a lot about the destruction that went on in Morrowind, actually. The entire island of Vvardenfell is a wasteland now. The inner sea still boils from volcanic fire and ash. The mainland was decimated by the Argonians, who now control it entirely. Mournhold was completely sacked.
Suffice to say that all remaining Dunmer have already fled to Cyrodiil, Skyrim, and Solstheim. There's very little they have left to call home.
Actually, we KNOW little. We can make assumptions. I read Lord of Souls and Infernal City. There really was not all that much to tell. They were near Vivec City in the book. Basically ground Zero. Of course that is going to have gotten the worst of it. There also is a god sent meteorite burning away in the boiling sea.You have zero evidence to support that the ENTIRE island of Vvardenfell is a wasteland. Tis true it was severely damaged but we have no evidence of it being a complete wasteland. That is pure speculation.
What are you an Argonians fan that is ecstatic that the place may have been destroyed? That is fine for your own speculation but do not try to pass it off like it is fact. We know of the area surrounding Vivec City and not much more other than Red Mountain exploded. Vvardenfell was damaged yes. But completely destroyed beyond reclamation? Very doubtful.
As far as Morrowind being controlled by Argonians? Again VERY doubtful. Maybe briefly after their invasion yes, and up to the time of Umbriel they sent religious parties out to the scathing bay for sacred ceremonies of some kind but that doesn't suggest they control the entirety of Morrowind at all. They certainly did not have any possession of the western areas near Blacklight and below, they were supposedly invaded by Nordic and Orcish mercenaries. If the Argonians held any major portion of Morrowind it would have been mentioned in Skyrim. The Dunmer there would have been outraged. Instead there is very little mention of any outright animosity between the Argonians and Dunmer which would not be the case at all. The only thing we know is that during the events of Umbriel, 160 years before Skyrim's events, the Argonians had various raiding parties throughout Morrowind and they had a religious ceremony tied to the scathing bay. While it may be the case that the Argonians had a large portion of Morrowind under their control it seems much more likely that they just swept through Morrowind and decimated large areas and disrupted the lives of the Dunmer people to a rather large degree and then withdrew most of their troops after they felt like they had got their 'vengeance'.
Conversation in Skyrim also seems to indicate Morrowind is a place that is safe to go back to as a few Dunmer iirc, were thinking of going back there now. In the beginning after you make your racial selection if you choose Dunmer they even say they will return your remains to Morrowind. There has to be something there for them to return your remains to that place.
TL;DR, Morrowind got effed up in the beginning of the 4E but most signs seem to indicate it is well recovered in Skyrim's timeframe with most of the Argonian invasion's presence being very much a thing of the past and not in any way active in 4E200 Morrowind.