The best fit is the bag that's most relaxed and comfortable for you.
There's no "right" answer to wearing a crossbody bag, even if handbag designers follow a similar trend regarding strap length. It's really up to the individual and your preferences.
It's a good idea to try on the handbag and adjust the strap until you find a comfortable and secure fit that works for you. It may also be helpful to consider the strap length when purchasing a crossbody bag. Some women love to wear them longer, while others favor shorter straps. But a longer strap may be more comfortable for some people or necessary for wearing heavier clothing.
It is also significant to be sure that the bag is not too tight or loose on your body, as this can affect the bag's stability and ability to easily access your belongings. The bag should not hang too low or be too high up on your torso, as this can be uncomfortable or inconvenient. A crossbody bag generally should sit at your hip or slightly lower, around your mid-torso. The strap should be adjusted so that the bag sits comfortably and securely across your body.