Over the years, some updates to Flow have been better than others, and others, not so much. If memory serves, the send an email action would use dynamic hyperlinks without much work, but something went sideways with one of the updates causing dynamic hyperlinks not to work as you’d want.
Here is a basic example of including a hyperlink in an outgoing email; further down the page, I’ll provide a more realistitc example.
In this example, I setup the Flow to trigger when an item is added to a SharePoint library. The key thing to note in this example is the value of the varHyerplink variable; note the double quotes around the link to item.