Period. Do not ever turn over your work until you receive payment.
What this client is asking violated your rights as a freelancer and as an artist.
Keep in mind that on Upwork, clients' credit cards are billed for fixed-price work BEFORE the work even begins. The money stays in escrow, waiting to be released to the freelancer. The money can ONLY go to the freelancer, unless the freelancer authorizes a refund.
Upwork provides a "Submit Work / Release Payment" button.
That is the button a freelancer uses to provide the complete files, not watermarked or disabled in any way.
The client has 14 days to review the files and request changes if necessary.
If a fixed-price contract is used, then the client does not have a right to ANY files or work that was not specified in the original agreement.
It is not appropriate for any freelancer to withhold agreed-upon deliverables until payment is released. That is not how the Upwork contracts and user interface are set up.