100m fastest drug/no drug is still gunna be the same person on a level playing field. So it’s still a fair race regardless.
You see it a lot in cycling. Quickest sprinter will be at the top of their game up until maybe 26-28 and then they lose advantage. Drugs won’t overcome one in a billion fast twitch genetics, only age will.
Endurance sports is where drugs make or break. Russia was a good example. They chucked their athletes into a program and suddenly their athletes went from cannon fodder to top end in their field in everything endurance related.