Not sure about the PEDs. As far as I remember he got punished for not attending a doping control; and not because he was tested positive. If Joe Joyce could make it, why wouldn't Yoka make it somewhere decent in the heavyweight talks. He's beaten Joyce in the amateurs and is younger. I'm not writing him off at all.
He missed 4 tests. 3 and you get a ban, but the French boxing federation turned a blind eye and tried to sweep it under the carpet by giving him a suspended one year ban which means he could keep fighting but if he failed a test or missed a 5th test he'd have to be banned for a year. But the French anti doping body didn't like the fact their rules were being ignored and took over the case and got him banned. As an Olympic athlete he should of been well versed in the requirements, the fact he missed 4 tests is more than suspicious. I've heard of athletes missing three and getting a ban, but never 4 and getting a suspended sentence. But yeah you can't write him off just yet, he was a top amateur but many top amateurs never make it as a pro and his style doesn't suit the pro game, if he's too succeed he will need to make a lot of changes.