Also I didn't realise that Enhance isn't actually making it, they're just publishing it. Some studio call Resonair/Monstars Inc.? Idk
Enhance is still the primary developer. It's Tetsuya Mizuguchi's
company, of which he is the only employee. He contracts the development work out to Resonair and Monstars who work with him to develop the game under his direction. The project is being built the same way it would be built if Enhance had actual employees. The article Wikipedia cites as a source mentions that Miz started Enhance after leaving Q Entertainment so that he could make the games that he wanted to make, whereas Q Entertainment was moving towards mobile stuff.
Monstars is Osamu Kodera's company, he was one of the programmers on the original Rez, Lumines, Meteos and Every Extend Extra which were previous games that Mizuguchi worked on. Resonair is also listed as working on the original Lumines.
He worked with the same two companies to port Rez Infinite and create the new Area X, so both companies are already familiar with the type of audio visual experience that he wanted to create. I think they did a wonderful job on Rez Infinite, Area X is one of the most amazing experiences that was available for PSVR during the launch window. There should be no reason to be concerned about the companies involved, since it's basically some of the same people that Mizuguchi has worked with for almost 20 years.
It seems to be pretty common for Japanese developers who leave a big company to form their own companies instead. Yu Suzuki did the same thing, starting his own company YsNet which is managing Shenmue III, where he contracted development out to Neilo, which is a company started by one of the programmers that worked on the previous two games. Hideo Kojima did the same thing, although in that case he didn't really have a choice and he hired his own development staff.