Ofcourse it is important, the camera, it is the tool you need to get the picture that you see already in your mind. But what about the quality? The picture above is taken with an iPhone 11. I know that is a good phone, but I had a picture taken with a Samsung S8, printed on a canvas of 100 x 80. First I had in photoshop the pixels doubled and then sharpened it. It looked great anyway.
So there is no need to blame your camera if you don't get a good picture. Mostly the camera does alright when it is on auto, but there are circumstances when it does not work so well. For instance in snow: your picture will turn out grey instead of white. But... that can always be fixed on the computer later on when you photograph in RAW.
I use a Nikon D7100 and used to have a D750. It also could have been Canons. But in the time, way back, that I chose, I found the Nikon sturdier than the Canon, that was more plastic. Later I DID buy a Canon for that reason: it was light and easy to bring with you. I disliked however to have to adapt to the other camera all the time and I did not want to buy two sets of lenses. So I stuck with Nikon because of my gear I bought sofar.
If I had to chose again, I would have gone with Canon. I like their service far better than that of Nikon, but that is personal. Someone else might have the opposite experience.
Besides those mentioned I now also use a Samsung S21 that has three camera's: wide, standard and tele. With that I take some great pictures too, but the resolution is a lot less of course.
Some notes on the D750
My camera had contiuous dust problems. I checked the internet and some had and some did not. So it was not with ALL the cameras. But after you cleaned the sensor within days you found these anoying spots in the sky again.
The D750 has been recalled twice. One time for a shutter failure and again some other time for another problem: flares when there was a bright light in the picture (not caused by the lens). So its reputation has not been flawless. I finally got rid of mine as I even got dust on my sensor after I did not even change lenses.
Another 'victim' complained with Nikon and they reacted with: userfault........ again an example of their great non-service.
Note that my D7100 had not been cleaned in years, though I changed lenses regularly.
I now use a Nikon D780. A camera that can be used as an DSRL and as a mirrorless camera when the mirror stays up and the back LCD works like with the mirrorless cameras. And so you have best of both. This too is a full frame camera and the followup of the D750. I have it for a few months now and am very content with it.
Also sharpness is not always important. It largely depends on what you photograph. I can imagine, that if you take pictures of buildings and other structures, that you want sharpness, even till the edges. But if you take portraits you like the eyes to be sharp, but some softness towards the corners is no problem. Nowadays people even hunt for vintage lenses, that have their own 'personality'. And most of these are not the sharpest :-) What is important is the image, even with a somewhat soft lens. No one is waiting for the technical perfect picture that does not speak to you. Most kit lenses that come with the camera you buy are doing well.
And if you want another one. Why not consider second hand? I bought some lenses and a camera second hand. You save a lot of money with that. It would be smart to buy in a store so you have your warranty.
So take what you have with you outside and use it.
Another thing that may help you find better pictures, is a piece of carton with a rectangular hole in it, matching the form of your sensor. When you look through that at the world, you see what you will catch on the camera. It helps you to learn to see what is important between all these colours and objects that surround you. You need to 'frame' it and isolate it from its surroundings. In former days we had those diaframes.... Maybe you can find one somewhere.