Despite what a few here might want to believe, can you say confirmation bias? You're actually spot-on.
While technically, dope was used in its present day context to mean cool or awesome in the '90s, it wasn’t as widespread or mainstream as it is today. Back then, like already mentioned, it was more niche, mostly tied to certain subcultures like hip-hop. One can deny, but this is fact.
Fast-forward to the last 10-15 years, though, it’s gone way beyond that. Social media, influencers, and younger generations have brought "dope" into everyday use, but it's starting to dwindle, somewhat.
From what I seen and heard, it's now mostly used by those trying to sound cool especially by the early mid-30s and older Facebook crowd, along with "da bomb" which again, in my experience seems to be mostly used these days by Asians, and it just sounds retarded. Besides, try saying da bomb at the airport. I'm sure those who still use it will say we are all grandpas and grandmas who take issue with it.
So yeah, dope might have started in the '90s, but it really blew up and became trendy more recently. Thankfully, it's used less frequently. However, like most woke and unhinged folks these days, they're trying to re-invent language and separate it from its original meaning. And yes, unhinged is my favourite word these days! 😜