I see that you are indeed a personal trainer so I am assuming you have heard varying opinions on this.
Depending on the placement of your feet and how much ROM is applied determines the target of the exercise whether it be the hamstrings, glutes quadriceps, and calves. However if this exercise is performed improperly the leg press can be very damaging to the knees.
When I started training I always remembered the – “toes in” targets “outer thighs” while “toes out” targets inner thighs with a 30 deg. angle in or out with toes and lowering weight until knees are @ 90 deg.
And then another issue is how far apart are the feet? 6-8 inches or wider?
I think it’s all a matter of what’s best for the individual depending on their body type and what they are most comfortable in doing.