I'm just going off of listening to drexel say it back in 2019 and reading the definition of urban dictionary before the word became a big meme.It used to be, and was for over a century. Then some dumbass misused it, a bunch of other dumbasses parroted the ur-dumbass, and now we have people desperately creating circuitous backronyms to "explain" why suddenly a word means something that makes no sense.
From what I can tell, the earliest modern use that isn't vague or probably coincidental comes from 2012 and probably came from the MGTOW scene. It very recently went from an obscure code word that only edgy internet losers used to a tired way to signal that you're a fad-obsessed dork who loves YouTube personalities.
edit: removed ngrams link because it doesn't actually have relevance due to the fact that "simp" was also apparently an extremely common abbreviation for something in the old timey days
People try really hard to prove that rappers were like totally saying it in 1980 therefore it's legitimate, but all known examples are massive stretches. For example, dictionary.com claims the line "Taking out all simps and suckers, y'all know the flavor, No Time" supports the new definition, even though it in no way does (and yes that's the entire context). Wiktionary says the line "A lot of simps won't like this song / 'Cause them punks like to hit it and quit it / And I'd rather stay and play" from Baby Got Back supports it, but again, it really doesn't. It's a massive cope because people would rather have the excuse that black people invented it, therefore it's cool. When in reality it was probably a bunch of 17 year old white guys who were mad at the world.