I think this security hold is a pure BS. No one was able to justify it.
And the argument "Upwork wants to make sure that your money is safe" doesn't fit at all.
Some projects take one or two months to complete, you have enough time to do your security checks during this period.
If you have finished a fixed price contract the funds will become available to you after the standard period of 5 days.
For hourly contracts check out this Help Article to learn how the billing cycle works. Note that if you finish an hourly contract on Monday, the client will be billed at the end of the week.
You can also check your funds by going to Reports and selecting Overview from the drop down menu.