Here is a fantastic article that cuts through all the conspiracy crap and goes over the actual timeline of the Russia investigation. It's a long read, but worth your while.
https://abcnews.go.com/Politics/trump-dossier-stuck-york-trigger-russia-investigation-sources/story?id=57919471
Trump 'dossier' stuck in New York, didn't trigger Russia investigation, sources say
President Donald Trump and his allies have long insisted that what he calls the “fake dirty dossier” was wholly “responsible for starting the totally and discredited witch hunt” by special counsel Robert Mueller.
But, beginning in July 2016, that so-called “dossier” actually sat for several weeks inside an organized crime unit at the FBI’s New York field office, even as counterintelligence agents in Washington, D.C. – unaware of the new allegations – were already investigating Russian efforts to hijack American democracy.