I too think this guy is on PEDS unfortunately.
if you follow his strava he posts the most whacky stuff, if he is this good legit, i think he should drop the ultra crap and just move over to the marathon, a lot of his miles today were 5:3x-5:4x, he split a 2:38 marathon while running 50 miles in harsh terrain, this guy could be a 2:10 marathoner if he applied himself.
It used to be my hunch that anyone with this type of rapid improvement has to be on the gas, but I just don't see enough money to be made here for someone to give Walmsley a legit drug program.
Remember, PEDs aren't as simple as taking an EPO gummy with your morning orange juice. They have to be done the right way to even work, and that requires some legit medical supervision. I have a hard time believing a company would pay a doctor enough money to risk his career so he could unethically prescribe and or/oversee an ultra runner's cocktail of drugs. All for what - so a few sponsors can get a bit of extra exposure? So Walmsley can clear 40k for the year?