Though the Monsterverse version of King Ghidorah is dead, an out-of-continuity event could bring him back, and be the driving force that unites the Justice League with Godzilla and Kong.

Source: https://screenrant.com/justice-league-godzilla-crossover-titans/

While it may seem difficult to fathom a giant moth battling other kaiju, Mothra is a worthy opponent to even the strongest monsters like King Ghidorah.

Source: https://www.cbr.com/godzilla-strongest-weakest-monsters/