It is trivial to have velocity written for SLW
with UE4 style mesh tessellation gone in UE5 we are left with no options other than using a high poly mesh plane to deform the ocean correctly unless the source code of the engine is modified to re-enable mesh the original mesh tessellation back.
There is a whole range of options to work with. And these days with niagara you don’t need source modified. Neither you need to rely on tessellation at all to get water surface geo. Not even it is geo that you need at all, but that is different story.
Niagara has a serious problem not being able to detect displaced triangles via World offset. This is something I’m still investigating, however the question has come up for years with no documentation anywhere to help make or fake this happen correctly and keeping performance in mind.
No, niagara does not have that problem at all. You want to get vertex data, you get it through mesh DI, and then repeat the same node network you use for WPO in niagara. Nothing of that is applicable to splashes, for which you need nothing but displacement render target.