Usualy caused by camber, because u said if steering stright car goes straight, either theres too much diff. Between left n right camber or both have too much camber

If at slow speed, if u keep steering straight, car goes straight right?

Depend on what car u drive, most cannot which is fine if u use stock tire size , wheel size and ride height.

If thats the case u shouldnt worry too much

I used to run on almost -2degrees on both side and the car became very sensitive to road crown.