You're not doing anything wrong.
I had the Pixel 7. The physical size wasn't the issue, but rather that the phone is top heavy because of the camera enclosure. Unlike other phones of its size or even larger ones like my friend's Note Ultra, the Pixel 7 always felt like it was going to fall out of my hand due to the top heaviness. I never got used to it and wound up using my old Pixel 5 for a bit before trading in the Pixel 7 for a Z Flip 5 which is much easier to handle despite being taller when open.
He does this a lot.