I ran into this recently at work and (short version), the answer was to download & use Reqnroll instead: https://marketplace.visualstudio.com/items?itemName=Reqnroll.ReqnrollForVisualStudio2022

According to their website (https://specflow.org/) SpecFlow won't be available after today, which I suspect was known well before this week, as for instance their GitHub issues got nuked some time ago, ex: https://github.com/SpecFlowOSS/SpecFlow/issues/2719#issuecomment-1934292742