Hi @AVignetti,
HubSpot automatically maintains date properties that store the date when a deal entered a specific stage:
Date entered [stage ID]: the date and time the deal entered the stage.
In other words, you could simply create a deal-report that shows the Count of Deal (y-axis) and the Date entered ‘Proposal sent’ (x-axis), then apply a breakdown by deal owner – and you’re seeing how many proposals are sent over time, broken down by rep.
Let me know if you’re getting stuck or have follow-up questions.
Best regards!