Question about water

Without using the unreal water plugin which is jank garbage, what are some methods you use to make water? I’m just getting into unweel engine, and I am working on water/trying to master the more advance parts of scripting/rendering.

I have a few questions:

Has anyone tried FFT water, or is it better to use a sum of regular sines in a matrix (but with simpler calculation than fft)

What is the best mesh to use for water? planes are not visible from the bottom, and when I did double sided, bottom turned black.
I tried the beveled cube, and that worked well (No disconnecting geometry)
But a regular cube disconnects at the sides. is there a way to cut seams in blender and UV map a regular cube so as not to disconnect the cube geometry when it has a sinewave on it?

When and where do you use: [particle water Vs. mesh water with code Vs. flipbook water]

Also, how do you fix disconnecting mesh like this without subbing the whole cube? I dont want calculations done on the sides as well.

i use double sided single layer water planes with refraction. to get underwater fx you gotta get creative with local postprocessing volumes and postprocessing fx. always been like that.

if you need water with big waves anything goes. displaced, tesselated, whatever. and shaders. be creative.