When I take the battery off, the inside information says: teracube Model : Tercube 2e Color : Black
FCC ID : 2AT6G-TERACUBE2E
So for sure it is 2e model.
At exactly what point does this happen? Before or after connection of the device?
It seams that it does not connect at all.
Correct udev will be required, were you confident you had that sorted?
You might find this useful reading https://totrdlo.ru/en/kak-proshit-povrezhdennyi-preloader-vo-vremya-proshivki-smartfona.html It is not really a how to, but demonstrates quite a high degree of background knowledge is required any time you have difficulties with a “bricked” phone.
Edit @Mehdi, I am not advocating any course of action in sending the above link. I am concerned however that the Teracube instructions show an image where preloader is 
. This is a difficult subject to explain; the article I linked, indicates that this is a very high level of intervention. One needs a very high level of certainty when following this path.
Notice how Teracube suggest
Download latest version of SP Flash here - we have made it even safer to use.
where SP Flash Tool Windows v5.2048-2.zip is linked from a Teracube server. This at least implies that is a “special” version.
It seems to me that development of v5 and v6 have gone hand in hand, there may be specific differences. Please don’t guess but ask !
I am very disappointed to hear that Teracube have not replied to your emails. Their forum support looks as if they replied to a number of serious questions. I hope you will try asking there.