Ground Zero installation failure : perplexing (and frustrating)

I have a new Dell 7780 with no installation; and a UEFI W11 installation USB.
I have used the tutorial
and all is ready to go. After booting from the stick I can successfully navigate the language / keyboard checks up as far as Find Disks.
All that is found is the stick itself and a Warning: "Cannot install to this medium". The internal drive is not seen.
I have tried just everything: specifically
1 Using a LiveLinux boot stick nuke the internal hard drive to nothing but \x00 on all bytes (using dd)
2 With the same approach create a blank UEFI partition unformatted on the internal hard drive (using gparted)
3 As #2 but also format the hard drive NTFS (no change) and then try exFAT (no change)
all in the hope that somehow the drive would be recognised and I could proceed with the installation from there.
All failed. Relentlessly, the only drive that the W11 boot stick recognises is itself.
(I did wonder whether Dell SafeBIOS incorporates some kind of protection against what it might judge to be a 3rd party intrusion - but all of the attempts #1 to #3 above rely on permitting a Linux Mint live boot to access the hard drive, which occurs with no trouble.)
Does anybody recognise this excruciating symptom and who can offer a way through this inexplicable barricade?
(Then I'll need to by-pass the equally irritating requirement for a Microsoft ID rather than allowing a Local login right from the start, but I see this has been raised already in this forum. So I'll take that on as it arises.)
Thank you for any assistance!

Did Linux actually accomplish what it said it did? It happened to me more than once under Linux that I dit a copy to or a format of a usb stick and that subsequently it turned out that nothing had been done because the stick had become read-only.

Most Dell devices ship with the disks in RAID mode, even if there is one disk. Get into the UEFI settings and switch to AHCI mode. Otherwise, you likely need to have the storage drivers available on the boot disk or another disk.

Reset BIOS or load defaults.
Set Disk mode to AHCI, not RAID
Select OS mode = UEFI
Disable fast boot and secure boot (you can turn it on after installation)

Windows can be installed in two ways: Legacy-MBR or UEFI-GPT
To install as Legacy-MBR you must boot the installation drive as Legacy
To install as UEFI-GPT you must boot the installation drive as UEFI.

As you have a UEFI BIOS, you should install as UEFI-GPT
Detach any other drives (SATA or Power cable) from the MB.

During POST, press F12(?) to launch the boot menu. You will see two options for the USB drive. USB UEFI (Name) and USB (Name). Select USB UEFI (Name) to install as UEFI-GPT
Go to install and delete ALL partitions on the main drive till you have one and only one unallocated space and then proceed.

Megahertz said:

Set Disk mode to AHCI, not RAID

Click to expand...

Thank you! THANK YOU!
That did the trick. Windows 11 Install saw the drive and I went from there.
But (isn't there often a but ..)
I stalled again two or three steps down the line.
Windows 11 cannot identify my internet connection and halted there.
(Strange - all previous machines back to and including Optiplex 790 (2012) and three new machines since have had no difficulty whatsoever wih this.)
I tried turning the router off in the anticipation that the step would be skipped but again the instalation ground to a halt.
What can new users with no internet connection do?
There is a real dearth of "Skip" buttons in this W11 installation procedure. W10 was rich in that regard.
I will try installing at a different property (daughter's) with a different network setup and cross fingers.
But otherwise - I feel totally stuck.
(Oh dear. A bit cross with myself that I nuked a working machine but frankly it was so glued with not particularly appealing characteristics that at some stage I would have had to do that, and thus ended up exactly where I am now.)
Cross fingers for the off-site installation but otherwise .. .. ?
Anyway: thanks so much again for your tip about RAID / AHCI.

As pseymour said, Most Dell devices ship with the disks in RAID mode, even if there is one disk.

Open Device Manager. What are the devices with a yellow alert of missing drivers?