How do you value recurring contracted revenue and project-based revenue within the same company?

Example: technology-enabled, solutions & managed services provider.

Well-run business, no one customer represents more than 25% of revenue, unaffected earnings or are negative impacts expected thus far given the pandemic environment, closed expected Q1-2020 sales, and forecast for the balance of the year will show a conservative 13% revenue increase.

2019 Revenue = $21M 2019 dollars Adj. EBIDTA = $2.2M $6.3M is contracted recurring support revenue (contracts go from 2-5 years), managed services. $14.7M is services/project-based revenue. 65% of the customer have been renewing project-based work for the past four years.
I realize there’s more detail required to come up with actual EV. Such as debt, a balance sheet that sort of thing, but what’s your thumb rule, what necessary calculations do you apply to the scenario?