The legs are so much stronger than arms that it is impossible to hold a heavy enough weight with the arms to make much difference in leg strength doing a goblet squat
If you are 120 pounds that is only one fourth your body weight
standing on one leg instead of two doing a squat with no weights is more intense than lifting 30 pounds
Also using weight machines allows you to add a lot more weight to what your legs lift than you can achieve with holding weights with your arms
Most non disabled non obese non anorexic healthy young adults can do the following throw with proper balance training by a qualified martial arts instructor
Anyone who can do that can lift twice their body weight on one leg or four times their body weight on two legs
Within at least a limited range of motion
I am not liable if someone copies this and gets injured I am simply showing this to demonstrate beginner level strength
Lift starts 1:56
This is a exercise library that certified personal trainers use
You should be able to find leg exercises more difficult than goblet squats but easy enough to do that do not require weights or equipment here
https://www.acefitness.org/resources/everyone/exercise-library/
Check off the drop down menu that says no equipment at the ACE fitness exercise library