html file opens as text if loaded from Google Drive with a browser

I have an index.html file which simply links to a list of PDFs in a sub directory. If I open this directly from a browser (be it chrome or safari) I can see the file and click and open it's content. I'm sharing this folder with specific accounts.

But if I have this hosted in a Shared Drive, when I click on the html, it does not load but shows the contents of the html. I have Google Drive installed on my desktop and if I navigate to the folder in question I can open it directly.

Right-clicking gives me options to open with Chrome or Safari, but for most of the others this was shared with don't get this option, particularly if they do not have Google Drive installed on the desktop.

Any ideas on how to change this so the file properly opens in the browser? I mean, if I double click on a PDF directly, then it opens.. TIA.