Hi Mopp_,
I had a similar issue and this guide fixed it.
https://forum.xda-developers.com/t/how-to-recover-from-any-hardbrick-or-red-case-in-9008-mode-without-any-boxes.4052841/
Try Spamming ( Holding Vol - plus Power and spam pressing Vol + ) to get into 9008 Mode. This should work...