It all depends on what the brake manufacture specifies on internal vane direction and not so much on the slotting.
Second this - internal vanes are sometimes curved or angled and it’s important to get them the right direction. Most OEM rotors on normal cars are just straight vanes and can go either way.
Slots/drilling on the surface don’t matter directionally and don’t really do much with modern brake pads besides look cool and wear out pads faster. Even track pads don’t need them with compounds that don’t get overheated easily. The only really useful thing they do anymore is a reference indicate the internal vane direction.
Slots and drilling came about because old asbestos and metallic pads that were not really good for track use, basically running constantly overheated so they glazed and offgasssed when pushed hard, and the solution was to have slots to scrape the pads clean and holes to vent the gasses.
As long as you’re using adequate pads and not running into pad fade (firm pedal low friction), they don’t do much. If you are trying to track on street pads, maybe it would make a difference, but it’s cheaper to just buy the right pads than burn through crappy pads.