Well I think this is all going off at rather a tangent !!! Firstly you don't need a new camera, it will NOT make your pictures any better. .... Camera's don't generally make good or bad pictures, what ever their vintage. But the person holding them makes a big difference.
Secondly the issue of using various modes and the sometimes insistence of using manual modes, under some belief it will make your pictures better... load of rubbish if you don't understand what is happening with the camera.
What it all boils down to is understand and controlling light. To this we have two basic controls, Aperture and Shutter. Or simply "hole" and "time". As I doubt many walk around with a hand held meter, we all rely on the built in light meter system to measure this light.
So it doesn't matter if you set or the camera does, you both relying on the same information. All the modes are doing is selection a preference or bias toward either exposure time or aperture. They are the only variables we have to play with. (ignoring ISO for now, assuming it's been set to fixed).
Where the difference is made is reading the setting either you or the camera is suggesting, and understanding the effect.
So a little test

So the camera has measured the light, and it reported 1/15th Sec at F8, using 100mm lens. What are you going to think and do ??????
Next day your are out shooting the landscape, nice building in the foreground, hills to the far, camera says ..... 1/1000th at F4.5 ......... what are you going to do ??????
Next question, if the meter reading is 1/2000 at f5.6 what will the speed be at f16 ????
When you have grasped these basic, then you can start to think about being more clever than then the camera's meter. Dialing in deliberate "errors" or "compensation" to the reading.
It all come to understand and controlling light, all camera's have had that ability since they were invented

.... newer and "better", just give you more options in the way you work. But some times all the technology and automation lets you down, if you don't understand the basics first.