sharepoint online – Editing (Modern Experience) Site Page Through JavaScript Using Page JSON Data

I have a web application that I want to edit/update the home.aspx page (in Site Pages doc lib), namely inserting anchor elements to instances of agendas for meetings. I already have the agenda meeting content itself stored in a Word file with its metadata in a separate doc lib). The JavaScript within the web application will make the necessary REST requests to read the ASPX file contents and write updated content. This home page is for board meeting members to click on the link, have a new tab window open that shows the agenda (HTML markup) and simultaneously offers the Word file form of the agenda in a download.

If this homepage.aspx were just HTML markup (HTML page), it would probably be easier to create an HTML file with ‘aspx’ extension to prevent default file download action in SharePoint. But the page would not be dressed with SharePoint chrome. I have used a REST request to get the JSON-formatted information of the ASPX file, but I don’t think changing the ASPX content by manipulating the JSON data and POSTing it via REST is the way to go.

The tip of my brain is not thinking of the easy solution. How is this done? Another task is to create an ASPX page in a new browser tab filled with markup and ensure it is surrounded by SharePoint chrome (not just a plain HTML page served up.