Is your feature request related to a problem? Please describe.
No.

Describe the feature you would like to see.
Option to have graves be safe from robbers until they reach a specific decay level. For e.g. safe until it becomes a forgotten grave.

Describe any alternatives you've considered.
Not really, since this option would allow for robbing graves, but only after a set amount of time.

Additional context
No. Cool mod.

I like this idea. I'm not sure when I'll get around to implementing it but I definitely will at some point, thanks!

I'm closing this as it has been added in 3.2.0 (which has been released for 1.19.2 so far, the later versions will likely come later this week).