This looks pretty cool ! the artwork is great too !
For the splash I would have done probably something very similar to what you did…
Metaballs can do interesting things sometimes but plain modeling and using subdivision surface to smooth things out is also working well…
Since it’s not animated I would say whatever works, at least I don’t see an obviously better technique…
For more complicated shapes you can try something like starting with simple geometry and looking into remesh to merge all that, but I’m not even sure this would work well outside of geometry nodes…
)
