MFR direct marketing vs. working through a commercial broker?

[Cooper Marcus]

I've identified ~50 properties in my target geography that I might like to buy - I asked my commercial real estate broker who typically reaches out to owners whose properties are not being actively marketed, and he said the broker does. However, I'm doubtful that my broker will want to, or will do a good job of, reaching out to all 50 of these owners.

From what I've learned of marketing directly to owners, I was imagining I'd do all the outreach, until such point at the owner was actively conversing with me about selling, at which point I'd start involving my broker.

How are commercial brokers typically involved in marketing to and sourcing sellers "at scale" like I'm describing here?