Health insurance for American moving to Germany? (Mannheim)

Hi, I am moving to Germany soon (Mannheim) and I am looking for some recommendations for health insurance. I need my own insurance in Germany as a requirement for my work visa. I have been talking to Cigna and other providers but I could use some advice. I am freelancer, so they require outside (non government) health insurance.

Does anyone have any recommendations, or has anyone been in a similar spot? Thanks for all the help and I am looking forward to seeing all you InterNations folks when I arrive in Monnem!

Cheers,
Eric