There's plenty of data on lighter and heavier balls since pitchers have been training with weighted balls for a few years now. It's mixed-some players benefit, some pitchers can't handle it and get hurt. Forcing everyone to throw a heavier ball is not a good idea.
Pitchers train with heavier and lighter balls, but you're never supposed to throw them max effort. Eliminating sticky substances last year caused pitcher injuries. When you've been doing one thing thousands of times repeatedly your whole life, changing it is going to cause stress and strain.
"Among players who trained with balls of different weights, 24% got hurt either during the program or the following season. None of the players who trained with only the standard ball were injured." https://www.insidescience.org/news/why-training-heavier-or-lighter-baseballs-could-help-pitchers-throw-faster