Hello everyone.
I encountered this screen on the attached photo
after using easy installer on my Galaxy 9+. All went went until the very last step. Factory reset doesn’t work, the phone became totally unusable. What can I do? 
Hi @Globale welcome to the /e/ forum. You do not quite describe at what level the phone is totally unusable 
The first thing to check is whether you can enter Recovery mode. Before doing anything you want to establish is TWRP was successfully installed or whether you have Android recovery. If Easy installer got to the last stage, did you already boot into TWRP?
One possible reason for this message is the possibility a Samsung or Google account was still on the phone from before you started this.
You seem to be showing us that you have TWRP installed. I cannot help if I have to second guess what is going on.
Are you able to get a log from Easy Installer?
Please do not see the following as a remedy to your situation, but can you tell me whether you got to the stage illustrated here and were you able to Wipe Data? Easy Installer stops on Tap on ‘Do not install’ - [Edit, TWRP.apk] - SM-G950F - #6 by aibd
