I love the franchise and I held back my judgement until watching the movie. But even after watching the movie, I feel utterly disappointed.
This is not the quality of writing and world-building fans expect from MIB. The characters interact so superficially, it's hard to take any of the relationships at face value because they all come off as actors being friendly with each other.
The plot was disjointed. There were so many antagonists and storylines, I'm almost convinced that they wrote out several plots for MIB 4 and instead of picking one concise story they decided to fuse it all into an amalgam of confusing plot points and character motivations.
I really could write full on pages why this movie didn't work- even minor details like continuity flaws of cuts, character actions and even flaws in how characters are conveyed interacting with objects.
It was a mess. There was some level of love and passion here, but it was very rare and every other moment watching this movie was irritating at best and borderline unwatchable at its worst moments.
I don't recommend this movie. Just watch the first Men In Black, I assure you that you'll get a similar but better movie experience. Besides, MIB: International is about 50% references to the first three films, there isn't much to miss in the first place.