For those who still mention USDT (Tether), I think this stablecoin is pretty much done. Even now, USDC is used more because of regulations (MiCA), let alone if OpenUSD is issued anytime soon. USDC still has the first-mover advantage in this space compared to OUSD, though, proven by the fact that so many merchants and services already accept USDC.
I won't trust any of them even if they are regulated coins. However I believe in the effiency of those called stablecoins as a trading tool and a mean of electronic payment, I still think they highly riskier than any other form of fiat money (I believe they are not cryptocurrencies in full meaning but a cryptographic form of fiat money just like any scriptural form), and that they represent a real threat to cryptocurrency in its basic concept.
Another major problem with those called stablecoins is the correlation with the USD. A decline in the value of the dollar, which can happen at any time for any unforeseen reason, can cause enormous losses for users of other local fiat currencies. Therefore, trust in the dollar is essential for trusting such projects.