I don't use WhatsApp, but you could try this, and see if it's at least a temporary fix.
Uninstall WhatsApp & download the March 24th or earlier version of WhatsApp from apk mirror. You'll eventually be forced to update it, but it'd be interesting to see if a previous version still crashes or not.
Turn OFF Autoupdates on the Play Store & Galaxy Store BEFORE you try this.
Let me know if WhatsApp still crashes using a previous version.
Here's the link apk mirror (It's EXTREMELY SAFE to download apks from apk mirror!!)
Given that both your device & WhatsApp are very popular, I think that it's likely just coincidence the issues you are experiencing happened after an update.
I'm pretty sure that if it was just Samsung's update, you'd be seeing 10s of thousands of reports on the same issue.
Try my suggestions, you've got nothing to lose.