Query about prepositions in names

[uberwolfie]

Greetings! I have recently joined IMSLP in order to submit my own new editions of some 16th century music, and realised after I created it that (unless I just typed it too quickly) the category/composer page auto-capitalised my surname, thus: https://imslp.org/wiki/Category:De_Jager,_Peter

I have convinced myself that this is correct with regards to cataloguing rules (according to the most authoritative sources I could find). Given that my name is of Afrikaans rather than Dutch origin, the preposition should come first in a listing by surname, and should be capitalised.

However, it should still not be capitalised when written out in the usual order, e.g. in my talk page linked above, it is technically correct as the title of the page, and after "Works edited by:" but then not correct as the heading to the left of where my photo would be.

My feeling is that surnames should be allowed to start with lowercase letters, then capitalisation rules can be applied depending on context. If this is impossible then I'd rather leave it as is, as (minutely arbitrary though it may be, and technically not relevant as I have lived in Australia my whole life) I would rather be represented in the list as "De Jager, Peter" (South African conventions) than "Jager, Peter de" (Dutch conventions).

Apologies for wasting your time with this thoroughly unimportant point, however if anyone has any thoughts on this matter I would be very interested in them.