80d wasn’t listed. Won’t focus right

Hello,

no matter what I do my camera just won’t focus on a subject. It looks fine on the screen but once I zoom in , the photo is just super blurry and dull. I don’t want that in my images. I know people say stop zooming in but it helps me know my images are sharp and I want my images to pass the zoom in test. I don’t know if it is my lens or the camera it’s self. But I try manual mode I try the automatic mode. I try single point auto focus. I try upping my shutter speed bring my iso all the way down since that ups noise. I try breathing techniques. It’s mainly when my subject is further away from the camera. Very close up it looks nice. It’s when I’m getting a full body image that it just looks horrible zoomed in. I don’t want to have to buy a new camera and lens. The 80d was already almost a 2,000 camera. I just don’t know what to do, but it just really bothers me when I’m taking pictures and then I do my zoom in test and they just look horrible.