Navigation bar gestures stop working

Hi,
It happens to my Samsung s9 with iodéOS 2.1 that after some time, without any evident (to me) reason, the navigation bar swipes stop working (currently i’m using the 2 bottom configuration, but when it happens they don’t work neither with the Gesture navigation set up).
The only solutions that I’ve found is to set the 3-buttons (all buttons always works) or simply to restart the phone.

In general it’s not a big deal and I’m not in a big hurry to have a solution, but it would be very useful to know how to restart the navigation bar without restarting the entire OS.

Thanks in advice!