This is the weakest of the of the "Monsterverse" series of films to this point. The CGI is all-out cartoonish, and it makes it nearly impossible to care about what's going on. Nothing looks real and I'm sure the creators of these movies have given up trying to make anything photo realistic. Or maybe it's an intentional choice because moviegoers actually prefer it to be unrealistic. Perhaps CGI has morphed into its own thing and realism is no longer required. That's probably the case and what a sad evolution that is.
The final battle in Rio is so chaotic that even though buildings are being smashed by monster fighting, none of it has any weight, structurally or consequentially. The scale of the monsters on the surface is diminished by the lack of anything to judge their size by when they are in "Hollow Earth". It's a lot like the old Godzilla vs. Megalon film released back in 1973. Godzilla and Jet Jaguar battle Gigan and Megalon and the whole thing takes place in an open field. The size of the kaiju is completely lost by having the fight take place in this setting. Hollow Earth promotes the same kind of scale problems. It's also a mistake to make these huge beasts move with the agility they do in this movie.
The Hollow Earth concept is lame and seems like it's a way to allow for Kong to still be the king of something since Godzilla is the dominant Titan on the planet. The humans in this movie are disposable again and this is even more evident when comparing this film to the far superior Godzilla Minus One, not to mention the stakes raised in Shin Godzilla.
The lack of dialogue, either by an important cast member being deaf or due to a lot of monsters growling and grunting, probably allows the Monsterverse movies to sell well internationally. The necessity for dubs and subtitles is greatly reduced. "You mean I don't have to read!?! Awesome!!!"
It actually pains me to have to write an almost entirely negative review. As a reference, I own EVERY Godzilla movie on physical media and consider it to be my favorite film series. Many, many of them are silly B-movies and some of them I don't even like, but none of them seem as formulaic or as tossed off as Godzilla X Kong.