I'd add, if your point of contact was the agent all the time, or landlord told you an agent will handle that further, I see no issues.
I'd worry only if agent came up out of the blue in the equation while you were talking only with landlord directly until now, then I'd check with landlord to see what's going on.
For example, for my flat in Berlin, we had agent show us the flat, Hausverwaltung signed the contract with us and bunch of people were there - 2x from Hausverwaltung, one from owner and Hausmeister from their side, I think I haven't forgot anyone, not sure if agent was there as well. Also, owner is a company.
I see term Regie mentioned often, I assume it's the same thing as Hausverwaltung, so maybe in your case agent == Regie, eg ones who will be your point of contact for any issues along the line.
And after some time they sold the building and old Hausverwaltung send us information about that, papers which we have to sign to transfer deposit between the companies and so on.
And owner just collects the money