Making one big water plane would probably not be feasible due to the limitations of the engine.
But I have (kind of) fixed the issue.
Making the waves global doesn't do anything, but by breaking the extents and bounds I forced them to be rendered always. (or a pretty sizable chunk of them anyway)
I have no idea what this will do with the performance if you spam it.
Problem is, it also crashes the editor and the game if you select the water planes "edited" this way.
So I added a version of the water which will not crash the editor but one that looks the same.
So first import the model called "_editor" put your water however you want it to be like and when you are done replace the model with the _boundless version.
So far it works on a pretty big map in-game like that, just make sure to not click the boundless model ever again, replace it back with the editor model if you need to adjust it or something.
To be honest I don't understand why the global sequence doesn't align up since the texture id sequence in global animation does.
I may have made a mistake or something, though I went through the model again and the global animation seems to be fine.
There is an alternate way that it might work, by extending the model outwards and making the edges blend in so that even if they misalign it probably wouldn't be very noticeable.
The problem is that it would require a custom texture, in other words a massive filesize.