Permanently delete apps using Titanium Backup (they keep re-installing!)
There are times Titanium Backup does not work, so I use System App Remover (root needed).
However, as indicated here, a workaround for Titanium Backup is to install Termux. Issue the following commands from Termux

su
setenforce 0


Then try to uninstall the apps again with Titanium Backup


  This sets SElinux to "permissive". Then you can uninstall all your system apps. Then after you reboot, the phone automatically goes back to "enforcing" for SElinux.