If update not available on your phone yet, Clear Data of ONE UI HOME.
And Gestures Navigation support is added in ONE UI3.0 for third party launchers.
If that helped or solved your query "Accept as solution" will be appreciated.
Before update I faced this problem and Clearing data worked for me every time.
Try Reset Settings once or visit service centre for software reinstalling.
That's what I did
Still no luck navigations are spoilt when there is a launcher
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