I do not understand that logic … fielding it, via the fair catch or the return, guarantees a starting position somewhere between the 5 and 15 … assuming a 10 yard return … split the difference and call it the 10 yard line.
Letting it go into the end zone places the ball at the 25 yard line.
The risk of it being down inside the 5 doesn’t outweigh the reward of getting it at the 25. Fielding it at the 7 or 5 doesn’t mitigate that risk-reward math IMO.
Let’s also recognize that this is college football not the NFL … punting isn’t the science that it is in the NFL