To be honest? Personally, I find all EVFs more or less unattractive compared to a good optical viewfinder (OVF), at least in daylight. Even the one in the A7Rv, which many claim is comparable to a ground glass screen, something I completely disagree with. For me, it's simply the least unpleasant. I also think that the optics used are at least as important as the resolution. For example, I find the 3.7MP EVF of the Z6 more pleasant than the 3.7MP EVF of the A7iv (and the one in the Z8 is supposed to be significantly better at the same resolution). And what surprised me most: In a direct comparison, I found the 3.7MP EVF of the A7iv clearly more pleasant than the 5.xMP EVF of the Leica Q3. The Leica owner, by the way, felt exactly the same.
Simply comparing the specifications on paper is completely pointless here. In my humble opinion.
Unless, of course, you're only comparing Sony EVFs with each other and assuming that the viewfinder optics are comparably good or bad. In that case, I would also say that 5.x MP is better than 3.7 MP and 9.x MP is better than 5.x MP.
But how significant the respective advantage is, and above all, what price premium it justifies, is certainly a matter of personal opinion.