FDA is in fact not required for backup software nor should it be. For example, Bombich is granted the com.apple.security.files.all entitlement for Carbon Copy Cloner, because backup software needs to just work without the user chancing a miss on the TCC prompt when they first set it up only to find out the app didn't backup their photos after losing all their data.

Apple stopped adding protected file-system domains for some reason, and have only expanded TCC to entail more vague and nonsense monikers. Sandboxed apps of importance like Messages, Notes, Reminders, and so on, all just end up under the "Full Disk Access" umbrella because they all store their databases in ~/Library/Containers, and FDA is really the only thing gating access to that. Apple should just start pushing the permissions one level down into that folder. Do I want to give an agent access to my Safari history, but not my messages? Too fuckin bad! No way to slice that right now, it gets full disk access and can access anything.