Hello, Olga Anishenkova
Welcome to Microsoft Community.
We appreciate your feedback and understand that this feature is important to you. While I don't have access to the specific roadmap, I can assure you that our team is constantly working on improving our products and adding new features. I recommend keeping an eye on our official announcements, blog posts, or social media channels for any updates regarding new features and their release dates.
I suggest you submit feedback to the developers so that they can potentially address this issue in the future. Microsoft often relies on user feedback to identify and prioritize fixes in their updates. If many users report the same problem, it’s more likely to be addressed by the developers. Click on ··· > Help & feedback on the upper right corner.

Instead of saving individual pages, you can create a master template document with all the desired pages and sub-pages. Then, share this template document with your colleagues and instruct them to make a copy of it whenever they need to create a new workspace. This way, they can edit the copied document without modifying the original structure and content. Although this workaround may require some manual effort, it can help achieve the desired collaboration in Loop.
Yuhao Li
Microsoft Community Technical Support