Can't Backup crashed High Sierra from TM: "could not find APFS system volume handle"

Hello Mac Users,

Yesterday I tried to install a driver for a usb audio interface which wanted me to give permission to load additional content via settings app. I did. Afterwards I couldnt get my Macbook to start.

Verbose Mode showed me this (unsupported CPU for reporter looks bad):

then i decided to run over my backup from external HD-Drive created with Time Machine.

Afterwards My Macbook still was not able to boot and showed me a Prohibitory Symbol.

Verbose Mode showed me this (sorry for the bad photograph):

It says: "ERROR! could not find APFS system volume handle" which i cant find any reference to online. There is always people referring to "could not create a preboot volume for APFS install", which is not my Errortext.

also i can't get into recovery mode. There is only the option to recover per internet.

I use:

Macbook 15" Late 2011, Samsung 850 EVO SSD 500GB,

latest Mac OS High Sierra I guess (hard to get more information since it doesnt start)
external HD for TM: Toshiba Canvio Basics 500Gb

Does anyone know what to do or even what my problem is? I guess its 2 different problems and the second one is about the APFS change since high sierra.