It's not a tough question, it's literally an easy, super-lazy question.
Literally a default meme on letsrun for decades "anyone faster than me is cheating".
The only correct answer is "did Ruth cheat? I dunno, we have to wait and see".
Here's a very complex hard version of the question (and answer)
Ruth ran 4:57 pace (per mile) average.
She has done that for half-marathon, more than once (only five others in the world too).
So the question is can she run twice the distance at that pace?
Pretty sure most would accept she can run 20 miles at that pace.
Many might also accept 22, 23 and perhaps even 24 miles before a blowup with modern super-shoes.
So did just have an awesome perfect day after previous failed attempts?
Did she draft her pacers well enough to make up the energy for the last few miles?
Did she improve her form enough to maximize the alphafly like others have done?
Is it some unknown new nutrition that would be made legal otherwise?
"possibly cheating, doping" is fair to put on that list but only at the end and even then you have to wait to see
It's a long road to 2028, we will see.