I think you are correct. Stablecoins will always have several layers of counterparty risk: The central bank that issues the fiat, the bank that issues the fiat-backed stablecoin (such as Tether), and the network the stablecoin is transferred on (such as Tron).

In fairness stablecoins have their own advantages. They are more private as you don't need KYC to send or receive them. They are also largely permissionless for this reason. Many cannot sign up for a bank account, but anyone can spin up a wallet on Tron.

This is not a defense of stablecoins. While I get the desire for them in third-world countries, I do not think the risks of stablecoins are properly understood by the average user. Bitcoin's volatility may be hard for a poor person to stomach, but at least that volatility tends to the upside. Stablecoins meanwhile can crash to 0.