I'm pretty sure there are plenty of people that think they never got it, but just had zero (or almost zero) symptoms and just never knew.

My son was born 4 months before the pandemic. Because he went to daycare me and my wife always felt like we had a cold or something. I tested and tested and tested even more. For me it was also really late (at least 2021, maybe even later) that one was positive. The actual thing was so much more mild than all those flu's and colds we had before.