Since the creation of this post I’ve managed to overcome the problem with the help of Romain Hunault.
These are the steps i followed that worked.
First of all, and that’s the clue, under the official Android ROM before flashing /e/ deactivate the SIM protection.
All the problems of SIM not recognised and no network after flashing /e/ were related to this protection.
You can deactivate all the other protections too.
Before flashing i recommend you use “Apk extractor” to backup some apps like Sketchbook.
The official apps don’t work in /e/ because the functionalities are deeply embedded in the system.
You must be aware that all the functionalities related to the Spen are lost.
- No handwriting apps and handwriting recognition, no warning when the spen is removed and so on.
So before flashing, under the official ROM, select settings / lock screen and security / other security settings / set up sim card lock / unlock the sim. Follow the instructions to unlock the SIM.
The following link was provided by Romain while we discussed the problem.
https://www.helpforsmartphone.com/public/en/samsung/android/android-6-0/guides/21/Secure-phone-Samsung-Android.
After this you can follow the instructions given in the wiki, but i had some problems with Heimdall so i used another approach.
First flash TWRP ( https://dl.twrp.me/hlte/ ) via odin
Copy the latest build of /e/ onto the SD card (https://images.ecloud.global/dev/hlte/)
Boot in recovery then MAKE A BACKUP on the SD card or … really recommended.
So tap the Backup button and make sure the backup is created in the external sd card
The necessary steps are described in the wiki under " Installing /e/ from custom recovery"
https://doc.e.foundation/devices/hlte/install.
Now you can enjoy your new os, free, with hlte.
Since I’ve installed /e/ i had no problems with the apps except the bliss launcher that i’ve replaced with Galaxy s launcher more stable. I’ve not activated anything under microG and all works fine (go away G…). Pay some attention to the accounts. Under the /e/ account you manage the sync parameters. If you have a low budget plan and don’t want to sync a zillion pictures this is the place where you get some control.
With my five years old battery i can still use it one to two days before charging. The lack of continuous tracking is noticeable.
Take a look under settings / updates. The team is doing a great job, the releases are very regular and the update process works very well.