There's no way to get rid of a link transfer if it was not uploaded from a WeTransfer account. Once you complete an upload, you'll have to wait until the transfer expires. Please check that you are sharing the download link with the right people before doing so.
If you've got a WeTransfer account, make sure you log in before starting an upload. That way, you can always look up a transfer in your 'Sent' log. Here's how to get rid of transfers from your 'Sent' panel:
Starting from November 2024, non-logged in users will be asked to enter a verification code upon sending files, creating a free WeTransfer account. This means that all transfers created from this moment on can be easily deleted by following the steps above. You can learn more about this change by taking a look at this article.