Yes, you can bridge your WMTx from Base back to Cardano. The official way to do it is through the World Mobile bridge here: https://worldmobile.net/wmtx/bridge
That page will walk you through the correct process. It uses Chainlink Transporter for moving assets between chains, and it supports going back to Cardano as long as you follow the right steps.
Just make sure you’re connected with the wallet holding your Base WMTx, and choose Cardano as your destination. The process might take a little longer compared to EVM-to-EVM transfers, but it’s all handled through the official route.
Always double-check you’re on the correct site and never approve anything from a random link. If anything looks off, pause and ask before moving funds.