Changing BIOS from Legacy to UEFI/BIOS so I can use Win 11 on this PC

What Volume Z means is this:

diskpart
sel disk 1
sel par 2
assign letter=K
exit
bcdedit /store K:\EFI\Microsoft\Boot\BCD /set {bootmgr} description "W-B-M"
exit
Shutdown and check during next startup if you find

• W-B-M

and

• Windows Boot Manager

somewhere in the BIOS Bootoptions. That is the place where you usually also find the USB-Boot-Option

If you find it, select

Windows Boot Manager

The problem we have is that the BCD-Entry and REG-Entry are different.

Only (!) when you found the 2 different entries from above you can continue

And ONLY means ONLY !

diskpart
sel dis 1
sel par 2
delete partition override
sel par 1
extend
shrink minimum=1025
create partition primary
format quick fs=ntfs label="Recovery"
set id="de94bba4-06d1-4d40-a16a-bfd50179d6ac"
gpt attributes=0x8000000000000001
exit

Otherwise only USB makes sense.
Depending on your USB, it might be necessary to disable Secure Boot first

More than 100 posts and isn't ready yet.

Would have been much easier and faster:
- Create a drive image of drive 1 on an external drive.
- Set BIOS to UEFI mode.
- For safety reasons, detach the power or SATA cable from drive 0 and then do a UEFI- GPT Win 10 Clean install on drive 1.
- Boot from the drive image rescue USB drive and replace the new Win 10 partition on drive 1 with the one on the drive image created above.
- Install Minitool partition and resize the recovery partition to 1G.

Another quick solution:
- Set the recovery environment on C: (reagentc /disable)
- Create a drive image of drive 1 on an external drive.
- Set BIOS to UEFI mode.
- For safety reasons, detach the power or SATA cable from drive 0.
- Boot from the Win 10 USB installation drive, launch diskpart, clean the SSD drive, convert it to GPT and create the 3 partitions:
EFI (fat32 - 100M)
MSR (RAW - 16M)
C: (NTFS all remaining space)
- Boot from the drive image rescue USB drive and replace the new C: partition on drive 1 with the one on the drive image created above.
- Boot from the Win 10 USB installation drive, and install the boot manager on the EFI partition.
- Boot into Windows, launch diskpart, shrink the C: partition in 1G and on the space created, create a Recovery partition.
- Set the recovery environment on the Recovery partition (reagentc /enable)

You should end with a partition layout like below

run just this command
C:\Windows\System32>shutdown /s /t 0

and this command should bring you straight into BIOS
shutdown.exe /r /fw /t 0
But not all machines support this command