you can buy an adhesive pen holder that has similar stitching which "sticks" on - they work well.

https://www.amazon.com/Notebook-Self-Adhesive-Designed-Notebooks-Calendars/dp/B082G744V3/

This is what I use for my daily driver / case - it's just made better and is superior in pretty much every way -

https://www.etsy.com/listing/1206035651/supernote-a6x-hardcover-book-looking?