Here is an update. After 3 hours of play, I noticed this "heavy aim". I checked the input lag and it came up at 56ms, which is normal.
Tomorrow I am gonna measure the sensitivity speed to check if its the same during "heavy aim"
When you get on, check the detailed diagnostic test results where it shows down speed, up speed, packet loss, latency etc.
Go into the advanced settings and change the port selection from automatic to manual, and redo the test using an alternate port.
I turned on my Xbox and had 85 latency, I do this and it dropped to 25 latency. Very significant difference in how it felt to play. High latency and NAT type can be fixed using this method. Both cause lag, what can feel like heavy aim, delayed actions on the screen where your shot seems to always come out late while the enemies doesn't. etc. Sometimes its server side, but these are in your control to a degree. So if people have issues with NAT not being open, high latency, this is probably the best first thing to do before you go into the router settings and set up port forwarding or try to do some other advanced fix. Sometimes it isn't necessary.
Sometimes these methods don't work and unfortunately sometimes the ISP just absolutely sucks. I cold start my Xbox each time I play. Its never left plugged in. So in my experience, turning it on theres the random port selected for me since it turns on under the automatic setting. It can either run good or not run good. It can be open NAT or moderate. This always fixes those 2 issues. I wish I could have even lower latency but this is the best I can get with what I have.