If Samsung Pay keeps crashing, you can put it into deep sleep rather than Uninstalling until there is a fix. Be aware that the Play Store will not update deep sleeping apps, but you can get the most recent update date by looking at it in Play (I am not sure if Galaxy Store will update sleeping apps or not)
Chanfing to button navigation does work, but I have just started to finally get the muscle memory of the newer gesture navigation working, so I will just keep the app disabled unless I really need it for some reason (like if I forget my wallet).
The persistent error clears up when you go back to button navigation instead of gesture navigation. Samsung Pay is aware of the issue and working on an update to resolve it.