Freelancing is a tough business, but it sounds like you have done well.
I did the same thing and went all in with one client. I didn’t build my reputation on sites like Upwork and Freelancer. When the work dried up, I had to start over with only my LinkedIn network.
Now I am trying other sources of income like article writing and blogging. So far, so good. I am building my list of clients and my own assets.
Good Article, Matthew!