Is it a Hosted Feature Layer?
Then go to its Item Details Page > Data tab >Fields. Add a new Field (Text). Keep the default length, if not more.
Next, click on the Table tab (Next to Fields tab)
Click on the newly created Field Name > Click Calculate > Choose Arcade.
In the Arcade Calculator, write a similar expression.
IIF($feature.IMAGEURL=='NA','NA',<a href="' + $feature.IMAGEURL + '"target="_top">' + $feature.SCIENTIFICNAME + '</a>')
You should be able to click the link from this field from both the new Map Viewer as well as the Table Widget of Experience.
Think Location