How can I make reports on Journal Entries show value for custom fields that are in rich text format?

I have created a report to pull historical data on custom fields that their format is Rich text. I was advised that:

"What happens normally when you set those fields to be tracked is that it will post the updates in the update stream and it can reference the text of the field at that time to be able to display it in the report. Rich Text is one of the only exceptions to this. Normally you can use the "Old Text Value" and "New Text Value" fields like you have, but Rich Text is stored in an HTML format in order to maintain the formatting that is being used.

Because of this, though the update stream can show that updates were made, the journal entry report doesn't have a native field in it that can pull and display that HTML text. It's a rare scenario, I think this only the second time I've seen this in the last 2 years or so.

In this case the only way you would be able to go about tracking changes in a report like this would be if you were to create a new field, probably a paragraph text field, so that the text can actually be referenced by the report."

Unfortunately, I cannot just disregard the already created Rich text format custom fields and replace them with Text fields as there are data populated in them within the system. Is there a way to create a calculated custom field that pulls data from the Rich text format fields and converts them to text, or change the report code in a way that I can convert the rich text value to text so that the report shows the data, or perhaps a function that converts Rich text to text?