correct treatment of von-part in Word bibliography

I was directed here from this thread:

https://answers.microsoft.com/en-us/msoffice/forum/all/correct-treatment-of-middle-name/d617e3a7-a5ff-4af3-95f7-dda49f33e5c7?messageId=ff78cc88-b9eb-4338-80b6-9a0eed447d9e

According to the Microsoft answer, I should seek help here creating a custom xsl file for the issue below:

Say Piet de Boer wrote a report in 2021. I want to cite this in Word. First name Piet, von-part de, last name Boer. I tried all available styles, Harvard is the preferred one regarding formatting the bibliography. But none of the available styles handle von-parts correctly. In the case of Harvard, the citation looks like

(Boer, 2021)

but it should be

(de Boer, 2021)

The bibliography also contains the entry Boer, d. P., which is ugly. When I add "de" in front of the last name, the citation looks proper, but in the bibliography the reference is sorted under "d" instead of "B".

How can I get the desired result? Citation: (de Boer, 2021) and reference in bib: de Boer, P. 2021 (sorted at B)

Thanks!