After the Awakening of the titans and the world realizing that Godzilla couldn’t be counted on in every occasion. Project Powerhouse was born and it emerged as a response to the realization that there were threats beyond Kong's ability to face. The project began after the Mechagodzilla incident, where it became clear that even Kong needed additional support.
After the end of the battle in Hong Kong, The remnants of Mechagodzilla were not sent to Area 51, as Bernie had initially assumed. Instead, they were taken over by Monarch and were utilized in their labs for something called Project Powerhouse, which aimed to augment Kong with heavy mech armor without the need for creating another Titan-sized mecha.
Now, this prototype was a remarkable piece of technology which is also called as the B.E.A.S.T. Glove. The B.E.A.S.T., an acronym for Bio Enhanced Anatomech Seismic Thunder Glove, encompasses Kong’s right arm, extending from his elbow down to the tips of his fingers, wrapped in a striking yellow colorED ALLOY that has some inspiration from the transformer Bumblebee.
The glove’s capabilities extend beyond mere mobility assistance; it significantly amplified Kong’s natural strength and punching power. The B.E.A.S.T. Glove boosted the force behind Kong's punches, empowering him with the might that was said to be able to shatter meteors.
Now as for the Jaeger’s easter egg inclusion in the movie, well, this was maybe just a coincidence or maybe they did it just for laughs. Maybe, just maybe, they were actually trying to create a jaeger type mecha for use by humans against titan threats in the movie but was pushed back to allow this to cook and emerge in a potential sequel. This isn’t far fetched as we already saw that they have the means necessary to create huge robot mechas and have done so in two occasions.