RIZIN just hired Michael Craven, a Westerner who was previously GM for New Japan Pro Wrestling. Under his watch, NJPW started subsets of the main company on multiple continents, and he brokered a US TV deal. They also ran a co-promotion one year with Ring of Honor during Wrestlmania weekend in Madison Square Garden. He brought in respected international talent, and helped NJ grow substantially in the international market. He was hired specifically to do the same for RIZIN, so the talk of them not caring about the international market is a bit dated. This became apparent a while ago, when they held an event in Azerbaijan. They're also holding an event in South Korea at the end of May.
They don't really have to compete with the UFC. It isn't the same product. They can grow on their own, and become a top alternative to the UFC, with their high production values, use of the ring rather than a cage (mostly), and infinitely better rule set (PRIDE rules + elbows, practically NHB). Perfect alternative for a guy like me, who is jaded and barely cares about the UFC anymore.
They're potentially getting indirect help from a UFC investor in The Rock, who does generally big numbers at the box office, and is starring in the Mark Kerr movie, directed by an Oscar caliber director in Benny Safdie (Uncut Gems) and co-starring Oscar nominated actress and Golden Globe winner Emily Blunt. Very possible that there is a reasonable uptick in interest in JMMA once that film is released, as a large portion of the film is about Kerr's time in PRIDE. They also announced that Ryan Bader has signed to fight the winner of their HWGP on NYE, not long after that film is released, Bader playing Mark Coleman in the film.
RIZIN will probably never become the top org, they don't really have to be. The event last night likely did over 50k in the crowd, and would have probably done bigger numbers if the grudge match that was supposed to headline wasn't canceled due to an injury. They hit over 48k at Super RIZIN 3, last year. They've got Japan on lock, now is the time to branch out. Plenty of things are playing in their favor.