I don't personally know enough about Upwork to answer that question.
I'm currently working as a developer consultant, and get all my clients from my previous work history. I used to work in an agency, building apps for many different clients, so now I've got a lot of connections in the industry.
Has it been complex to sell your skills because of your previous employee? Did you just cold e-mail your previous contacts that you got while working or did they approach you?