The solution mentioned by @jbl4ir essentially works.
Here’s how I’ve done it - I created a function that accesses the NavigationConfig from FSlateApplication, and setts the bAnalogNavigation to true/false.
#include "Framework/Application/NavigationConfig.h"
void AMyPlayerController::ToggleThumbstickUiNavigation(bool ThumbstickNavigationEnabled) {
if (FSlateApplication::IsInitialized()) {
TSharedRef<FNavigationConfig> currentNavConfig = FSlateApplication::Get().GetNavigationConfig();
currentNavConfig->bAnalogNavigation = ThumbstickNavigationEnabled;
FSlateApplication::Get().SetNavigationConfig(currentNavConfig);
}
}