Hi there,
Trust wallet Only allows to trade / swap Erc-20, BEP2 & BEP20 standard tokens in the app. The coin/s you have aren’t in any standard of these. Due to this, You can’t swap your Doge coins in the dex. Please move them to any exchange platform and trade there.
Learn more about built-in DEX here: What Is The DEX Inside Trust Wallet?