This would require an exchange that supports USDT transactions on both Tron (as TRC-20 tokens) and Solana (as SPL tokens)
Some multi-coin crypto wallets can interface with a lightweight exchange (Changelly, etc) so you can swap crypto at whatever market rates are at the time. Some have additional support for purchasing crypto, especially in smaller amounts (under $500).
If I were to take a guess as to how to exchange your tokens -- Tron is legal in China. It also isn't widely used outside of China. Binance was a big supporter of Justin Sun (Tron's founder) from the very beginning. If the Binance wallet is legal or grey for US Citizens, that may be a good place to start.
