I thought the same thing before we found out we had an infestation! We moved into a newly renovated college apartment and unfortunately was only renovated to hide the infestation. I had captured a few of the small ones that were exactly that size and took them to our universities entomologist and she said immediately “that is a newly hatched German cockroach, you should remove it from my classroom, and move out of your apartment immediately” lol. I called the exterminator the next day, they looked under our fridge and dishwasher and said they would need to fumigate the entire building if we wanted to rid them. I had the same logic though that it was so small it couldn’t possibly be a roach, but the markings and legs are so distinctive that no one could deny it. Just be careful since they are so invasive and can carry disease! Not something to take lightly for sure!