One of the major reasons US consumers shop with megacorp over small business is because of the no hassle returns.
The customer almost always wins those. And the merchant always has to pay a fee for the chargeback, even when they win, so they're incentivized to avoid them.
The merchant agreement isn't as effective as a well enforced law, but it's pretty close.
I would be fine with waiving my right to returns but this is not possible on purpose, so my only options are to shop somewhere else (often not possible) or found a company (not possible because it would be Liebhaberei - "Running a company without intent to make profits").
The type of thing that might go from side gig to actual long running business that could end up employing a bunch of people.