Manufacturing a fake loss with a false valuation is not the same thing at all - you've just said that "if you can do fraud, then sure there's money to be made from losses". Fraud makes money? Sure! Losses do not.
It is literally a thing. I cannot for the life of me make sense of how to make it work that doesn't strike me as off, but enough people get utility out of the moniker that it's got a page. So...
Tax loss harvesting is real, you just time when you take a loss to offset a gain. Then immediately reinvest. You haven’t lost any money in total, you can just claim the loss on your taxes (but will pay higher capital gains in the future).
This way you get to post a net loss.