Do you think USDC is also a fraud? They're eating into USDT's market share at an alarming rate... If USDT is really insolvent, the collapse should happen pretty soon.
Personally, I have always held USDC in high regard. Their attestations (not audits, which they have also never done) are now roughly 3 months late and they have recently changed their wording from being 1:1 backed by dollars to being backed by various approved investments. [1] It was right at the time they made these changes that growth went parabolic.
I'm also suspicious that right as the crypto downturn hit they suddenly went out to raise $440M - something I wouldn't expect a stablecoin with billions in the bank to need to do. [2] However, personally I would assign them a risk score of 3/10 ("Hmmm") as compared to Tether's 11/10 ("Oh sweet mercy") - a sentiment echoed by the Fed [3].
IMO there's a few things propping up USDT, including multi-stablecoin liquidity pools doing automatic arbitrage against other stablecoins.