Do not listen to people telling you to travel and do a border run once your visa is approved. If you put your travel date on the 17th in your application and the visa is not approved yet they will ask for a flight ticket at a later date. If you already flew and cannot provide it they will refuse your application
I had to submit invoices sent to clients for October and my bank statement with the payments of the invoices received. Plus up to date company documents and my Upwork profile with customer reviews. They really check that your activity is genuine and that it generates enough income to live. I don't think it would be accepted in your case.