In WokDocs, it appears that there is a default expiration date for folder links. Is there a way to change it?

You can do Optionally, for Link expiry date, choose the date when the link expires. The link expires at midnight on the specified date.

Note : You can share file links inside and outside your organization, but you can only share folder links internally.

Reference : https://docs.aws.amazon.com/workdocs/latest/userguide/web_share_link.html