Paying Engineers with Rev-Share (I will not promote)

I’m about to start a new business as a design founder. Previously, I worked with an engineer on Upwork, and he’s now proposing a revenue-sharing arrangement for my upcoming venture. This looks attractive to me because paying his hourly rate would put a significant strain on my finances. However, a friend warned me that revenue sharing could become problematic once the business grows, since the engineer would always receive a portion of the revenue. Offering equity isn’t currently feasible because I plan to move to another country this year and would likely form a new company there. I’d love to hear from anyone who has experience with revenue-sharing models in their startups. What are the pros and cons, and what should I consider before agreeing to this kind of arrangement?