Home depot rents pressure washers for like $35/4hrs. They include soap injectors to add concrete cleaners with the spray, but you can also just dump cleaner on the ground, brush it with a broom then pressure wash.

There’s also a ‘floor maintainer’ which is often used to clean/polish concrete. Either with a bristle brush attachment or various grits of pokishing pad.

As others have said, 100% use PPE. Face mask, gloves, eye pro. Concrete dust contains silica which leaves you with silicosis and bird poo (well any animal poo really) contains some rather nasty diseases humans can contract. Keep yourself safe.