Removing DRM fails with these log lines

[mtVna]

stdout+stderr from file dialog helper: ['', '']
piped data from file dialog helper: ['\x90\xf0\xb6p\x01\x19\xac\xec\xe5\x98\x96\xc3e\x07B\xad>\xeb\xabg\xfd4dzn\x18f\xc2\x80\xc4$\xa9', 'C:\Users\john\Documents\My Kindle Content\B00XWGQUHQ_EBOK\B00XWGQUHQ_EBOK.azw']
DeDRM v6.8.0: Trying to decrypt B00XWGQUHQ_EBOK.azw
Using Library AlfCrypto DLL/DYLIB/SO
DeDRM v6.8.0: Failed to decrypt with error: The .kfx DRMION file cannot be decrypted by itself. A .kfx-zip archive containing a DRM voucher is required.
DeDRM v6.8.0: Looking for new default Kindle Key after 0.1 seconds
searching for kinfoFiles in C:\Users\john\AppData\Local
Found K4PC 1.25+ kinf2018 file: C:\Users\john\AppData\Local\Amazon\Kindle\storage.kinf2018
Decrypted key file using IDString '250197790' and UserName '6a6f686e'
DeDRM v6.8.0: Ultimately failed to decrypt after 9.6 seconds. Read the FAQs at Harper's repository: https://github.com/apprenticeharper/DeDRM_tools/blob/master/FAQs.md
Running file type plugin DeDRM failed with traceback:
Traceback (most recent call last):
File "site-packages\calibre\customize\ui.py", line 172, in _run_filetype_plugins
File "calibre_plugins.dedrm.init", line 626, in run
File "calibre_plugins.dedrm.init", line 576, in KindleMobiDecrypt
DeDRMError: DeDRM v6.8.0: Ultimately failed to decrypt after 9.6 seconds. Read the FAQs at Harper's repository: https://github.com/apprenticeharper/DeDRM_tools/blob/master/FAQs.md
Traceback (most recent call last):
File "site-packages\calibre\customize\ui.py", line 428, in get_file_type_metadata
File "site-packages\calibre\customize\builtins.py", line 285, in get_metadata
File "site-packages\calibre\ebooks\metadata\mobi.py", line 498, in get_metadata
File "site-packages\calibre\ebooks\mobi\reader\headers.py", line 295, in init
File "site-packages\calibre\ebooks\mobi\reader\headers.py", line 323, in identity
UnicodeDecodeError: 'utf8' codec can't decode byte 0x81 in position 0: invalid start byte

[mtVna]

I retried with newer version of DeDRM:

DeDRM v10.0.9: Failed to decrypt with error: The .kfx DRMION file cannot be decrypted by itself. A .kfx-zip archive containing a DRM voucher is required.
DeDRM v10.0.9: Looking for new default Kindle Key after 0.5 seconds
searching for kinfoFiles in C:\Users\john\AppData\Local
Found K4PC 1.25+ kinf2018 file: C:\Users\john\AppData\Local\Amazon\Kindle\storage.kinf2018
DeDRM v10.0.9: Exception when getting default Kindle Key after 0.5 seconds
Traceback (most recent call last):
File "calibre_plugins.dedrm.init", line 943, in KindleMobiDecrypt
File "calibre_plugins.dedrm.kindlekey", line 894, in kindlekeys
File "calibre_plugins.dedrm.kindlekey", line 382, in getDBfromFile
File "calibre_plugins.dedrm.kindlekey", line 382, in
File "calibre_plugins.dedrm.kindlekey", line 127, in encodeHash
File "calibre_plugins.dedrm.kindlekey", line 119, in encode
TypeError: unsupported operand type(s) for ^: 'str' and 'int'
DeDRM v10.0.9: Ultimately failed to decrypt after 0.5 seconds. Read the FAQs at noDRM's repository: https://github.com/noDRM/DeDRM_tools/blob/master/FAQs.md
Running file type plugin DeDRM failed with traceback:
Traceback (most recent call last):
File "site-packages\calibre\customize\ui.py", line 172, in _run_filetype_plugins
File "calibre_plugins.dedrm.init", line 1030, in run
File "calibre_plugins.dedrm.init", line 981, in KindleMobiDecrypt
DeDRMError: DeDRM v10.0.9: Ultimately failed to decrypt after 0.5 seconds. Read the FAQs at noDRM's repository: https://github.com/noDRM/DeDRM_tools/blob/master/FAQs.md
Traceback (most recent call last):
File "site-packages\calibre\customize\ui.py", line 428, in get_file_type_metadata
File "site-packages\calibre\customize\builtins.py", line 285, in get_metadata
File "site-packages\calibre\ebooks\metadata\mobi.py", line 498, in get_metadata
File "site-packages\calibre\ebooks\mobi\reader\headers.py", line 295, in init
File "site-packages\calibre\ebooks\mobi\reader\headers.py", line 323, in identity
UnicodeDecodeError: 'utf8' codec can't decode byte 0x81 in position 0: invalid start byte
Added B00XWGQUHQ EBOK to db in: 0.2
Added 1 books in 1.1 seconds

[ElleKayEm]

Looks like you need to install the KFX Input plugin.