Portrait mode

Since I bought my iPhone 12 Pro

I realized that whenever I use the back camera portrait mode, the blurry effect isn’t well focused. In most cases the background wouldn’t be affected by the portrait but rather the person or item that is being snapped. Then in other cases it won’t pick at all or the blurry effect would be scattered ranging from the person/item to the background. I’ve tried checking my camera settings but it didn’t help. Please can someone give me a good solution because it’s frustrating. Thanks.