Rand to Garmin address book?

Are you referring to saved places, custom POIs or something else? Garmin GPS and address book doesn't connect in my mind.

Not to hijack the OP but perhaps there's some similarity. I inadvertently deleted my recent places. Assumed "wrongly" that delete would delete only the one selected.
Anyway... is this file accessible to save/edit?

According to the link I’ve provided, you cannot delete individual items from the Recent list. At https://support.garmin.com/en-US/?faq=1cBLsqOrtX5p4g5LPLpDI9 it reads “You cannot delete individual items from the Recent list.” That may be due to the “Recents” content being updated regularly as you make selections, add to, etc. On my Garmins the “Recents" is limited to 50 entries, the oldest being discarded as I add new and reach that 50 limit.

Hopefully someone can help you but I currently don’t have access to any of my Garmins so I can’t investigate the feasibility of your request.

You need to bring up each one of the recents you want to keep and then save it as a favorite. Then delete your recents and go forward from there.

Garmin doesn't have an address book.

Lesson learned about the deleting thing.
Trouble with favourites is they leave icons on my the map, I like an uncluttered map.