Still using a closed source wallet until now is not a good choice even with Electrum. I think you don't put Bitcoin in Trust Wallet but use it as a wallet to store coins and tokens. Even so, be careful for the security of your assets even though you keep your seed phrase well. In addition to keeping your seed phrase well, making sure not to be connected to the internet is an important thing that should not be ignored.
Yea, close source wallets are not advisable to be used, especially trust wallets, but electrum is not a closed source wallet as far as I know.
Electrum is the best wallet with user experience who already use it as a Bitcoin storage wallet even though Electrum is still called a software wallet.
Trust Wallet is a popular wallet for users who don't care much about security and don't care much about experimentation.
One thing that even makes TrustWallet more dangerous to be used as a Bitcoin wallet is because they are being used for multichaining all of the wallets using and sharing the same phrase, so if by any chance the wallet owner connects the wallet to any dapp that exposes the phrase, it will end up endangering not just the specific network the dapp supports but everything that's connected to the wallet phrase is in danger.
In addition to being closed source, storing Bitcoin on a multicoin wallet is not a good choice in my opinion. There are open source multicoin wallets like unstoppable but still I personally don't dare to use it as a wallet to store Bitcoin.