It should be obvious to anyone following profesional sports that everyone at the highest level is suspicious to a various degrees.
It is obviously one thing when lets say your blood bags are found with doctor Fuentes or you are trained by Jama Aden, etc, however any super high level result is suspicious itself.
It helps that client has a gradual improvement trajextory and is identified as great talent from very young age, but that does not guarantee that there is no doping or at least grey stuff.
I am admittedly very much fan of Ingebrigtsens and especially Gjert and Jakob, however do note that all three brothers are asthmatics and use meds just before races. So one cannot simply say that it is entirely clean result. I and anyone else can only hope that asthma meds is the iceberg but not the tip of it.
At the end of the day, the higher the money, the more incentive, therefore, even though bball, tennis or football are skill based, I would think that the level of doping there is very much similar to endurance sports if not higher