Greetings,
You are correct about the Boot Configuration Data. As you can see, my BCD is different from yours. You are missing the UEFI path.
I suspect your migration is what has led to your current situation. What did you use to convert the existing install to GPT? Did you clone, or actually migrate? There is a difference. It looks like you cloned your existing install.
Leaving the former boot drive attached. This is never a good idea, in fact, when you do use this method, the disk you are cloning to (destination) should be installed in place of the current boot drive (source) prior to the clone operation. This avoids the incorrect BCD above. After the clone, the source disk should be removed or disconnected before booting into the OS for the first time.
My BCD for reference:
C:\WINDOWS\system32>bcdedit
Windows Boot Manager
--------------------
identifier {bootmgr}
device partition=\Device\HarddiskVolume4
path \EFI\MICROSOFT\BOOT\BOOTMGFW.EFI
description Windows Boot Manager
locale en-US
inherit {globalsettings}
default {current}
resumeobject {2f3c1b92-1ebb-11eb-b07a-cdaf4537ddef}
displayorder {current}
toolsdisplayorder {memdiag}
timeout 30
Windows Boot Loader
-------------------
identifier {current}
device partition=C:
path \WINDOWS\system32\winload.efi
description Windows 10
locale en-US
inherit {bootloadersettings}
recoverysequence {2f3c1b94-1ebb-11eb-b07a-cdaf4537ddef}
displaymessageoverride SystemRestore
recoveryenabled Yes
isolatedcontext Yes
allowedinmemorysettings 0x15000075
osdevice partition=C:
systemroot \WINDOWS
resumeobject {2f3c1b92-1ebb-11eb-b07a-cdaf4537ddef}
nx OptIn
bootmenupolicy Standard
C:\WINDOWS\system32>
My Disk Management for Reference:
I think you should be able to fix this.
You'll need windows 10 boot media.
Disconnect the old boot drive
Start the system and enter BIOS
Make your changes discussed above
Insert your windows 10 boot media
Use F10 in BIOS to save and Exit
On restart use F12 to select one time boot device
Select path to your W10 install media
Select Repair or the Recovery Environment
Select Command Prompt
At the prompt type >bootrec /rebuildbcd
Select your windows installation to add and press Y
Exit and restart. This should allow the system to boot. Let us know how it goes.
Use the following for reference:
https://www.thewindowsclub.com/rebuild-bcd-windows-10https://www.thewindowsclub.com/how-to-repair-the-efi-bootloader-in-windows