Trustwallet sounds very convenient .....but how to use it privately and sudo-anonymously - is that really impossible ??
What is it exactly that you're trying to achieve? If you want to hide from TrustWallet SPV servers, then you could simply use Orbot VPN mode however, if you're trying to be anonymous so people can't link back to you and your addresses then you've got ChipMixer for BTC, Tornado cash for ETH or you could just use Monero.
And if you're referring to TRC20 (USDT) then I'm not aware of any methods for that. However, you could run your coins through exchanges or centralized services (obviously in this case, your transaction won't be so "anonymous", not for the exchange anyway)