@Jockpo523
Depends on how you look at it. I'd argue that free will never existed to begin with. Your thoughts and actions are ultimately decided by your emotions, desires, and sensations which you don't get to choose. They're just pre-programmed into you by evolution. Really every thought you have and every choice you think you make are akin to a series of dominoes falling over.
But setting that aside, it's not as though humans will be wearing shock collars that zap them every time they think of doing something evil. The evil ideas will never even occur to them. In fact, considering that he seems to be able to erase the past as well as the future, humanity's capacity to do evil would never have existed in the first place. She's not forcing people's hands, but altering their nature, which is something that's always been happening as a result of evolution. It's the difference between being doing a task because you've been enslaved, and doing a task because you want to. Whether you consider that still a violation of free will is a matter of personal definition.
The potential scope of human action will be reduced, but you could argue that because evil actions often violate the freedom of others, her plan would actually result in a net gain of free will for humanity. For example, slavery would never have existed nor exist again. Removing diseases like aids would also give people extended lives to further exercise their free will.
I don't believe that Makima is solely seeking power, simply from past experience with the author. Usually likes to give his characters more interesting motivations. My prediction is the series will climax with her attempting to use Denji to kill the death devil and the potential fallout from that. But I could be completely off because this author is one of the few I find genuinely unpredictable.