Can only relate to cars. Slots and drilled do help with cooling and cleaning away the brake fines and thus stopping power.
In really high stress like racing some prefer the slots that don't go all the way through.
I see a lot of smoking and or fire brakes on semis coming down mountains. I don't know if it would help in their case. They need much larger brakes and brakes on steer axle.
there might be some definitive answer. It does work or race cars wouldn't use them.
the best of all world are the carbon ceramic disc and they are drilled. They wear longer and give way more stopping. Don't know if they are available for heavy vehicles except airplanes.
Would probably cost a grand each. I think they want 5 thousand to change over our AMG.
By brand name disc that are properly heat treated and if grooved or drilled great. Don't buy the sold cheap for cosmetic effect ones.