How to Calculate Historical Pipeline Conversion in Salesforce

Curious how other RevOps teams calculate historical pipeline conversion in Salesforce? When you look back at a quarter, how do you calculate conversion across all pipeline that could have closed in that period? Pipeline that was open at the start of the quarter, created during the quarter, or pulled in or pushed out along the way. I’ve seen win rate and cohort-based conversion used a lot, but those don’t seem to capture what actually happened to the full set of Salesforce pipeline expected to close in a quarter. Do you rely on Salesforce reporting or snapshots for this, or do you handle it outside the platform?