Try making your own water using Blender 2.92.
Instructions are really simple, add a cube mesh, scale it to the size you need it (assuming it needs to be large, make sure it is scaled up until you can’t see its horizon). Make sure to go to edit view, use the right click button and click subdivide, as as many subdivisions as you need (you probably don’t need to go above 20 or 30, adding too many will make too many triangles).
Open shader editor and add a material, then you can copy what I took a screenshot of.
Use Shift+A and search the names of the boxes, and connect them accordingly. Change up the Musgrave scale and detail to what you want it to be like. If everything goes well you should have water. Export it as OBJ and import it into Roblox Studio as a mesh. You can color the mesh there.
Not sure if this works well, you might be better off using a water texture instead of making a mesh. You probably need to deform the water in Blender before exporting it, it might come out as a block.
You could use this water I made with a tutorial, but just know that it is flat and doesn’t have waves. I did include a script in there to make the water look more animated!
I’m not quite sure if this matches your style though.
Yeah sorry, this isn’t the kind of water I’m going for, I might use it in the future though!
Yeah, it does come out as just a block, and I don’t know what deform will mean in blender.
Your building style reminds me of the game Animal Crossing, if you go to Animal Crossing Water Example you should be able to find some references.