Get rid of apartments and make them instanced houses instead. There. Since you insist that it'll bankrupt Square Enix to solve the problem rather than alleviate it for some reason. Without having any kind of poll or anyone and being so wildly out of touch about the issue that you think people want smalls and they're entitled for wanting anything larger: that's your solution. Which would allow for them to not have to actually add anything and just repurpose something else. Same instances, generally less deco count, etc. Skyboxes aren't hard to make, and multiple could be made to simulate different zones without requiring walkable geometry. Aside from that, plots are flat. There's your exterior. The interior is already in the game. I promise you people aren't furious about the fact that they can't place 20 more items in their yard for people in a ward to see. They could just make apartments a magic box, and dozens of people would even be happy with that as lazy as that would be.
Regardless,
You're back here again spouting this shit as fact when you don't know that. You have no idea how much it would cost, but FFXIV is their most profitable venture. Rather than have it fund projects like Guardians of the Galaxy and Forspoken with its absolutely dogshit script, I'd prefer if it was put back into the game. If this were the actually the case, maybe they'd be able to keep up with a couple of hobbyists in terms of assets, and actually making QoL changes to the game that people feel the game actually needs; that unfortunately, some people have made in order to make up for their failures without breaking anything. It stands to reason that because they don't, they aren't. This is why they very likely have budget to spare and aren't appropriating it right. This is why I don't name Yoshi P in particular whenever this topic comes up, because it isn't necessarily his fault so much as it is Square Enix. So please, stop the riding. It's actually really sad.
Also, wasting time on the definition of what instanced housing is doesn't help. Everyone knows what it is, pretending it's inconsistent just because people have different ideas of what it would look like is disingenous.
It's functionally what apartments are. People don't want them because they are small and have pitiful decoration limits compared to larger houses. An instanced house would either be simply an interior, or one exterior that leads to the interior that doesn't have a persistent exterior location in a ward. Like I said above. This already technically exists, and players can already technically get them by owning an FC apartment and a regular apartment concurrently (which isn't regulated by how many plots are available), but the location you "enter" is the size of a shoebox and has a small decoration limit.