Bella is an office worker not a chemist she doesn't know how the drugs work so none of this is reliable as proof of a mind control drug. It could be she just got high and did things she's ashamed of and now she regrets it so she's telling herself that it was the drugs not really her. We consistently see portrayals of the characters in denial or trying to justify their actions. Using drug or alcohol use as an excuse is something that is common in real life.
It's a plot device added by the dev/writer to help the reader/player understand the game. Your slippery slope of a justification isn't rational for a reader to use. By that explanation there is literally nothing the dev could install for the reader to see that could not be debunked. How Bella came upon this information is irrelevant to helping the reader understand the plot and story dynamics. You're being stubborn to accept the devs method to inject story information is only hurting yourself.
One can just as easily say that any chemist the dev could magically write in to explain something could also be a blatant lie. The dev used an easy way to help the reader understand a concept and you refuse to believe it is true when everything in the story suggests it's true? I believe and trust Bella waaay more than I trust the hacker who helped the MC install spy software, and he is one of the few characters that has been generally trustworthy, but I still don't trust him.
I was simply pointing out that you yourself admit that this is a
mind control game at its entire core. The fact that you are willing to accept hypno videos in this games universe as valid but not a mind altering drug as valid until proven is just wild to me. Because mind controlling videos are further from reality than actual mind altering drugs are from a possible reality.
The dev is also intentionally using everyday denial and justification excuses in his characters explanations throughout the story intentionally because just like you, the MC and other charaters are trying to rationalize their behaviors and thoughts based on their understanding that no such chemical and video technology exists in their universe either, it's the dev trying to replicate genuine human reactions to their own denial of impossible technology.
But again, the fact that you are plainly unwilling to accept a fact in a games universe as truth until the games creator breaks the 4th wall and spells in plain language, and continue to believe what you want, is only hurting your own story experience. That's on you I guess. I've done what I can to explain it, you are just gonna believe what you want to believe from an inherantly Mind controlled based story.