How to do some iterate with ordinary nodes like directional warp?

Unless you fully know the internal workings of 'Designer' I don't think you can easily conclude that one approach will require more resources than the other. In fact.. I'd even argue that if we could use an iteration then it would only add up to what would otherwise be an x amount of "warps", because one way or the other you'd always need to go through all the warp cycles.

Therefor, as far as I know your best option here is to duplicate the node with Control-D and then add it to your node sequence. Repeat when needed. Not only do I doubt that this gobble up much more resources, it will also make it much easier to customize the graphic in the future because it'll be much more clear what is happening.

Many sections of Designer require a different way of thinking because they don't behave as more commonly known programming or scripting environments.

Hope this could help!