To delete system apps and keep them *not* coming back after reboot.
Download this zip: https://forum.xda-developers.com/sho....php?t=1646108
Flash it in recovery. When you "install" it youll be greeted with the aroma file manager ui. Now, from it open terminal and type "mount system". That way you will be able to see system/app folder which contains apk's. Now, close terminal and you are again in aroma file manager ui. Now go to system/app, press and hold on the folders/apks you want to delete but keep in mind that you need to know the package name of that apk so that you can later delete its data too. Then, go to data/data and delete folder with the name of that package name
For example, in system/app I had folder: Facebook_Client, deleted its apk, then went to data/data and deleted: com.facebook.katana.