I have tried to use OpenFixture and it seems that procedure to export from Kicad to DXF now is not compatible according to the indications given in OpenFixture documentation. [https://tinylabs.io/openfixture-kicad-export/]
This is the available options in the last Kicad available version

It seems that the needed option "use auxiliary axis as origin" now is not available anymore in Kicad.
Then is not possible to proceed according to the procedure.
I have tried to use OpenFixture and it seems that procedure to export from Kicad to DXF now is not compatible according to the indications given in OpenFixture documentation. [https://tinylabs.io/openfixture-kicad-export/]
This is the available options in the last Kicad available version

It seems that the needed option "use auxiliary axis as origin" now is not available anymore in Kicad.
Then is not possible to proceed according to the procedure.