Matt is correct. Pretty much everything on the market these days is very good and will outperform a D90 in almost all respects.
He's also correct that raw files are intended to allow the photographer (or editor, if a different person) latitude in processing the raw data to create an image. This comes with the price of spending some time post processing, or at the very least spending some time setting up the in-camera JPEG processing settings to give the type of results one wants.
Having said that, there are differences between different classes of cameras that makes one type better for one type of thing and other types better for other things. There is no single camera that does everything better than all other cameras. There's not even an "either this one or that one" duality. There are lots of choices with various strengths and weaknesses, advantages and disadvantages.
When one buys a single camera to do more than one type of photography, one has to weigh the advantages and disadvantages of each camera for each type of photography and decide which is the best compromise for them. Or one can buy more than one camera to use for different purposes.
The D500 is optimized to be an exceptional sports and wildlife camera at a very reasonable price. It does this very well. At the moment it is the "best in class" APS-C sports/action camera. It even offers a few advantages over much more expensive full frame "sports/reportage" cameras such as the Nikon D5, Canon 1D X Mark II, and Sony α9. If sports/action/wildlife is the primary purpose for which you are buying a camera and you don't want to spend a small fortune on lenses to get the telephoto "reach" you need, the D500 is certainly an excellent choice.
There are, however, other cameras that do better at things such as "natural light" portrait work and "ceremonial" photography, particularly in low light environments. These cameras have larger "full frame" sensors that give them better low light performance and give other desired stylistic advantages, such as shallower depth of field with lenses having the same focal length and maximum aperture, than any APS-C camera does. But to get the same angles of view that an APS-C camera gets, they require longer focal length lenses. This can be an advantage for wide angle photography, but it's a disadvantage in the telephoto range. Comparing the price of a nice 200mm f/2.8 lens for an APS-C camera to a 300mm f/2.8 lens to get the "same shot" with a full frame camera can induce serious sticker shock!
The good news is that most portrait and "ceremonial" work doesn't usually require anything longer than a 200mm f/2.8 lens with a full frame camera. The bad news is that doing sports/action/wildlife with a FF camera almost always requires at least a 300/2.8 or a camera with a high enough density sensor to crop substantially (which puts an APS-C body such as the D500 with higher pixel density and faster handling right back in the conversation).
Then there are the workhorses that are used by photojournalists who above all require a camera that can take punishment day in and day out in all types of shooting environments and continue to work dependably. These are typically lower resolution full frame cameras that are very fast and built very solidly. The Nikon D5, Canon 1D X Mark II, and perhaps the Sony α9 (which is not quite as impervious to hazardous environments, particularly those involving water, as the other two). The build quality adds significant cost to the price of the camera. But the ability to shoot half a million to a million frames without requiring any major maintenance pays for itself in the long run - if one is going to shoot that many frames before the next generation or two of camera comes out.
If sports/action/wildlife with lenses that don't cost more than a modest used car is your top priority, then the D500 is probably your best choice on the current market.
If portraits and "ceremonial" photography in lower light is an area where you can't compromise, the D850 is currently a better choice if you have high quality FX lenses to use with it. But be prepared to pay more for the lenses you'll need to do sports/action/wildlife or to spend more time working in post processing to crop your images and massage the cropped raw files from the D850.
Or you can get a D500 for sports/action/wildlife and a D750 or D850 for portraits if you have some decent enough full frame FX lenses. The same 70-200mm f/2.8 that works fairly well for sports/action/wildlife on a D500 also does very well for portraits and other moderately low light photography on a full frame FX body. The same 85mm f/1.8 and 105mm f/2 lenses that work well shooting sports in a gym with a D500 will also allow brilliant portrait work on a D850.