It used to be that swiping down would lock the screen and swiping up would show Control Center. But when iPhones lost the home button, swiping up took up its click behaviours. Swiping down from the left for locking the screen and swiping down from the right to show Control Center is indeed somewhat awkward, but it’s not immediatelly clear to me what alternative they could’ve gone with that would leave you with the same level of quick access as before.