My theory is that she came into things clean with big dreams but in 2017 she realized how much further ahead everyone was, and how they were all probably doping. She had improved her 5K time dramatically since turning pro, but was still at 15 flat, which just wasn't cutting the butter on the world stage. She wanted more so she turned to her resources and started doping.
And I say doping. Not grey area. Dope. I'm sick of grey area, there is no grey area, there's cheating and there's not cheating.
But she rationalized it in her head, because I think she felt guilty knowing that not all of her teammates were on the dope and they were watching her dramatically improve while they remained stagnant. She thought "if I don't wear the shoes, it doesn't count as much". She thought "if it's not crazy, like EPO it doesn't matter." and she started racking up titles and records and looked like a real medal contender. But she slept like a baby at night knowing that her top competitors do worse, and she "doesn't wear the shoes".
Her relationship with Centro will always be a weird red flag. That they broke up shortly after she was busted also rings suspicious.