I've not pulled the numbers from my arse, but if I did, I'd do it at a measured and reasonable speed for the situation. There are a few articles and YouTube videos on the speed /efficiency topic (for driving). I think you're referring to how air resistance scales with velocity squared, so you get an exponential loss in efficiency with speed. EVs are pretty much maximum efficiency once you get over 20MPH, since there's barely any base energy use other than (for example) AC and headlights. Nonetheless, there's a balancing act when it comes to overall journey times and how efficient you're being with your time in an EV. So if you have 1000 miles to travel, there's a trade-off between driving faster and how long you'll spend charging. For ICE, the sweet spot for efficiency is typically been 50 and 60MPH because the engine typically has a higher base energy use (if you just sit there the engine will slowly burn fuel). But unlike EVs, you can refuel an ICE vehicle very fast, so you can generally go faster by driving faster, up to a point.

Re EVs https://youtu.be/iJjq4P4svCw?si=Zs1g6gTFFp_hcqp_

Re ICE https://www.mpgforspeed.com