Opportunity Tracking for Recurring Customer

Hello, I work with sales ops for a construction materials company and recently I was pulled into another division to assist with their Salesforce rollout. But there is a big question mark which looms in terms of opportunities.

Their specific business works mainly off of recurring business with contractors. They connect with one and throughout the year get shipped material based on needs. Their VP wants them to put the opportunity in as an annual amount for the year, but wouldn’t this open them up to an unbalanced funnel that would be hard to track?

Their targets are a yearly forecast divided by 12 on a monthly basis.

Sorry if this is the wrong sub, but does anyone have experience with this scenario?