Hi Doctre_P,
I go through your post carefully and as per your description, when you use a trigger when a new file is added to a folder in SharePoint online document library you cannot get the hyperlink (URL) as Dynamic Content.
May I know have you check for a "Link to item" option in your Dynamic content. Link that can be used to get to the file or list item .
Also, please try with the trigger “when a file is created (properties only)”, then you could get the dynamic content Link to item.
Meanwhile, could you please upload a screenshot of your trigger flow here for better understand and we test in our side and verify the result with you.
I appreciate your patience and understanding.
Best Regards
Waqas Muhammad