With rubber stamps in particular you’ll likely want to go to the Advanced layer settings and enable the ‘Ramp’ feature. This will ramp power towards the edge so you have a supported block for the parts of your rubber doing the actual stamping.
I tried to find a video as we don’t have any self-produced ones, and this one, while a bit dry, does explain it: Making a Hand Stamp Co2 Laser With Ramp Edge Lightburn - YouTube
One of my colleagues @Rick detailed this in a prior forum post here, that you may find very useful: Stamp or Ramp settings - #9 by Rick