@Tiejo: If you head to Settings > Display > Navigation bar > Swipe gestures > More options, do you have 'Swipe from bottom' or 'Swipe from sides and bottom' enabled? Have you tried increasing or decreasing your gesture sensitivity to see if you notice an improvement?
Same issue on S21 FE, only after android 13 update. It seems like there's a gesture control added for grabbing an app or window from the bottom right corner to minimize into recent/open apps (if you continue to hold your finger after the swipe, you can move the window around as a grabbed object), and it's actively fighting against the swipe to back gesture as thet're located & activated in almost the exatc same spot, but I can't find anything detailing this or how one would deactivate the grab & minimize gesture. Frustrating, have been looking for days and this is the first time I've even seen other people mention it.
Using a Z Fold3 here.
Updated to Android 13 recently after it came out.
I'm using Swipe Gestures (instead of the "buttons" navigation bar) with the swipe-up from the right being my "Back" button. On WhatsApp (ver. 22.214.171.124), the swipe gestures literally just FAIL occasionally. The only way out is literally by restarting/shutting down the phone, or by accessing Settings via my edge-panel >> Apps >> Settings. In Settings, I either set my Nav Bar to "buttons" and use it for a while, or set "buttons" and then a few seconds later, set it back to "swipe gestures".
The same thing happens when I'm using the native Samsung Internet browser, too.
Really annoying...hope this gets fixed soon.