I am also open to DSLR recommendations.
OK, first off, compared to 10 years ago this is a fantastic camera. TBH there aren't really any bad cameras sold these days, and they're all incredibly capable. Possibly the most important think is for you to actually handle one and see f it feels comfy in your hand, if you can see through the viewfinder easily and the controls fall to your fingertips. This has a full frame senor, and it should be very very capable in low light. If you want to do shots in really dark conditions then you'll probably need a tripod and possibly a lens with a larger aperture (the lens you suggested has an aperture of f4, which isn't very wide - as aperture gets wider the f number gets smaller - you would want f1.8 or f1.4 for hand-held low light. We can talk more about that later, and you could research.
I have my own set of preferences (I use Sony kit) but the camera you suggest is absolutely fine and much better than anything most of us started with in the digital age - I was a film user long before digital and even before autofocus cameras.
This is my weak point, I have zero knowledge of modifying photos with photoshop, as with phones almost don't need tweaks and you can do in the phone itself.
OK, first off software really falls into 2 categories, although there is some cross-over between: Image development and pixel-level editing.
Pixel level editing is for making major changes that are irreversible: photoshop is a pixel-level editor, and is a very complicated tool that's not really suited to your needs.
Image development is for processing pictures to enhance them, so changing exposure levels, tone and colour, applying sharpening, controlling contrast, removing dust spots etc. This is the kind of software that you will need to enhance your images. Nikon have their own software tha should be free to a Nikon owner, and there are also other packages, paid for and free that are suitable for this. We can advise as your needs develop (pun not intended).
Don't get too hung up on the camera or software at this stage. Also don't get sucked into the idea that to use a camera everything must be set manually - use of automated modes makes life much easier for most of us, and we only use manual when necessary. But pprobably the most important thing will be to just get out and take pictures, developing an eye for a photo and not worrying so much about the technical details.