Have you enabled 'Full Immersive' mode at all using 'SystemUITuner, 'ADB ' or 'SettingsDatabaseEditor' as this happens to me when Full Immersive is active, as it takes one swipe to show the Status Bar then another swipe to initiate the Gesture.
There is a setting that stops that behaviour, but for the like of me I can't remember where I seen it, pretty sure it was something along the lines of 'allow gestures in full screen mode'.
But if Immersive isn't active you could try increasing the sensitivity of Left & Right gestures in Nav-Bar options or try using the alternative 'GoodLock' gesture control.
Pretty sure you have to disable gestures in Nav-Bar settings first though, otherwise it will override GoodLock.
⚠️ YOU'VE BEEN WARNED ⚠️
FYI, if you haven't used SystemUITuner b4 and you decide to give it a go, backup your device settings in the settings page first & don't be blaming me if you bork your device, as some options are hidden as they are either not compatible with your device or conflict with ONEUI, examples are the 'NightMode' setting, enabling it on ONEUI can leave you with a blank screen, also some settings glitch out and default to 0, like setting a custom value for the Back & Right gestures or setting a custom 'hold delay' value.
⚠️ YOU'VE BEEN WARNED ⚠️
