How to ask a good question Item 3. This is probably best asked as a new topic rather than resurrecting a months old topic.
You might have better luck using the Xpath transform if this is will formed HTML.
Do not escape the /. It is not needed and changes the meaning of the /.
The regex in OH isn’t quite the same as what is used in regex101. You must generate a pattern that matches the entire document with the part you want to return to your item, and only that part in the ().