What you want to charge are "fees" which is money you get to keep in your pocket.Some charge an up-front "pet fee" which is a flat fee the tenant pays for the privilege of having a pet.

If such a flat fee service does not exist, what are some things I should consider before investing my time in getting licensed?

Buying the remainderman position in a life estate is a more typical arrangement...there was even a movie about a guy who bought one for a Paris flat..

After starting that job, I started saving money as fast as possible to house hack and renovate a 3 flat in Chicago.

The one I live in and another 2 flat which profits $900/month.I want to accelerate my real estate investing with the BRRRR Strategy but I am having a hard time calculating all the costs.

I pay 8% gross rents collected for property management, others pay $50-$100 flat per door .  

With my PM here in E TN we charge 10% flat with 50% first months rent also. 

Some managers don't charge anything for maintenance, others charge a flat fee of $X per call, and others charge a percent of the total invoice.

We've had a minor drop, but YOY listings for our office are virtually flat, only off by one in May

I'm purchasing a 3-flat in Berwyn soon, with all three units occupied on month-to-month leases.