sharpening japanese carving knife

[Enricopg]

hello, I want to sharpen this carving knife:
https://www.dictum.com/en/marking-knife-kogatana-standard-double-bevel-blade-width-18-mm/710201
I read the instructions if I am not wrong the recommend using the SVD.186 R and MB-100 with one diamond stone. To me this is impossible to do. Too expensive. Isn't there another cheaper way to do it? I tried to do one free hand. I am not crazy about it, although there was an improvement compared to my previous method with waterstones.
Thanks Enrico