ok my only experience is with CGC and its been a good one however it looks like they dont do DS carts with out cases even if they didnt normally come with cases:
https://www.cgcvideogames.com/news-a...t-graded-items

that may change, it may not, who knows.
I would avoid wata from all their past drama so that leaves VGA. You might shoot them an email and ask them straight up.

anything in my collection that holds a value of over $1k monies i would slab too. sadly slabbing a sharp NES tv is far from practical at the moment