By the end of the film, the Precursors seem to have a greater hold on his psyche, and in the next Pacific Rim film, the stage seems set to see good Newt and bad Newt square off to see who gets control for good.
Throughout Pacific Rim Uprising’s second and third act, we see Charlie Day’s Dr. Newt Geiszler become more and more compromised by a Precursor presence in his head.
Considering Charlie Day did a pretty good job laying the foundation for this battle throughout Uprising, seeing him go full throttle for one final charge is too good of an opportunity to pass up.
This leads him to do a whole bunch of stuff he wouldn’t normally do, like compromise the defenses of humanity, almost choke out his best friend / foil Dr. Gottlieb, and wear crisp, flashy suits.