Is there a way to make a roll off the character sheet buttons private. The selection returns as a whisper but the final result is public.
It depends on the character sheet. The OGL doesn’t have a way to do this, but the Shaped 5e sheet does.
working with the pathfinder sheet
You should be able to adjust "most" of the sheet's rolls based off of settings>sheet configuration>roll configuration You can set PC and NPC sheet rolls separately as either public or whispered.