Back when I was a road warrior (and my home country wasn't in the EU), one time in ZRH they actually took me to an office aside to check the stamps. I gave them my passport and wished them good luck - at the time a passport would usually last me about a year until full. All my stays were short and a lot of them not in Schengen, so I was definitely not overstaying, but tracking all the stamps in a full passport... after 20 minutes, they gave up 😂 I feel whatever you tell them upfront, they would still have to check (or at least try their best) themselves.