Netgear Readynas NVX (Buisness)

I DID IT GUYS. Thanks so much for all the help from Sandshark​ and StephenB​.

So I managed to install Debian 12 32bit instead / wanted to run OMV, on the internal HDD. So no need to have a permanent external USB for this at all and it boots automatically into the HDD aswell. 

I started with a normal USB installation from usb via the recovery mode trick outlined, the annoying part was the part that i needed to modify the .cfg to work in text mode. I installed everything into the hdd as one partition. Then i rebooted into the usb again but this time into the debian rescue mode so i can access and mount the flash. Here I still dont understand that much, as i blindly trusted google Gemini, but i simply formated the whole internal flash and installed a newer version syslinux onto it. I also copied the initrd.img from /boot to the internal flash as the initrd.gz and aswell the vmlinux from /boot into the flash. I then modified the syslinux.cfg like this:

DEFAULT debian

PROMPT 1

TIMEOUT 50

SERIAL 0 9600

LABEL debian

KERNEL vmlinuz

APPEND initrd=initrd.gz root=UUID=f35db2a4-c8f7-48c9-ad98-adba65473e1b ro console=ttyS0,9600n8 earlyprint=serial,ttyS0,9600

and rebooted.
And it boots directly into debian YAY

But as the internal ethernetport didnt work i still needed to use an external wifi adapter to get this working. But luckily 

https://github.com/jimmyw/linux-intel-e1000gbe-driver
This worked perfectly. Just needed to comment out the hard coded path line and it copiled with no issue on debian 12.13.

I still dont understand the whole process 100% but i hope this somehow helps anyone with similar issue as me