I suppose you tried to send USDT ERC20 token from Kucoin to trustwallet and then to coinbase which was a very wrong choice because you are going to pay double fees which are insanely high.
What you should do next time is to transfer directly from Kucoin to Coinbase, and please use a network that requires low fees.
For example; This is the only fee you will have to pay to withdraw from Kucoin and deposit directly to your coinbase addresses and then you convert the coins back to your preferred coin, USDT
1. Avalanche (AVAX) - 0.01 AVAX (~0.65 USD) in fees
2. EOS - 0.1 EOS (~0.45 USD) in fees
3. XRP - 0.2 XRP (~0.2 USD) in fees
4. XLM - 0.02 XLM (~0.007 USD) in fees
5. LTC - 0.001 LTC (~0.19 USD) in fees
However, if it doesn't go through, then all depends on the seriousness of Trustwallet. I don't know them but they seem to be a centralized wallet provider. So in my opinion, if until Monday your transaction is still stuck, you should contact their support and they may try to revert the transaction. This can be done, but it may require manual action from them and so it's possible they charge a fee.
It's a noncustodial wallet, so support won't help
Your coins wouldn't lost, if there's no miner confirm or validating your transactions your coins will came back to your own wallet usually around 2 weeks.
This applies to Bitcoin network, I don't think it applies to Ethereum network too