Have tried both version from the site as well as from Google Play. It doesn't even run now. Previously, it would run for a couple of days or so before crashing. Also want to add that I have Trust wallet, metamask and Blockstream's green wallets installed with no issues.
Thanks for the replies and suggestions, guys. I don't have any anti-virus app installed but there is Knox running, of course, so some security stuff. I don't know why that should be killing it but I can't see anything to confirm. I'm running Android 11 on my Note 20 so I think I'm pretty up to date. I haven't encountered this type of issue on any app before that I can remember.
Can you try to install the apps not from the Playstore instead directly on electrum.org.
You can download it from here
https://download.electrum.org/4.0.9/There are two option try the arm64 v8a and test if it won't crash but if it doesn't work uninstall it again and try the armeabi v7a version let see which one will work on note 20.