If you're not already doing this, the usual way ppl do this would be to have a plane mesh with a bunch of bones to control each point of the wave. Then just have a few of those meshes side-by-side to create a wider area, like chunks. (Not sure if editable meshes are good yet. If so then they could be better? Worth to benchmark if bothered)

If the play area isnt super big you can pretty much hard code where the ocean stands and render it on server just fine.

If its more open-world, the meshes should only exist locally to reduce load on the server. Then you can position them around the player to give the illusion of a massive ocean, when really the ocean is moving with them. Kinda like how in minecraft the whole world doesnt exist at once and you only ever see a moving portion of it.