>>46597796DHL fucked-up shipping calculators, or at least whatever Holo used before is the one fucked-up and Holo was losing tons of money.
Basically, as long as your item can still fit on a standard padded envelope, or a small box, it will be fine. The price for the art book is pretty damn good honestly for how heavy it is.
But the moment the item become odd-sized, or be pretty big, DHL used the biggest size of boxes they have that can fit your item's dimension. This is important because DHL charge based on box size (mostly). Unlike EMS who only charged based on weights, mostly disregarding of your item sizes.
Hololive shop should at least provide EMS as alternate option.... but I guess it will step on Geekjack's toe since EMS shipping is their entire shtick. Geekjack is still listed on their overseas buying link.
Buyee is still available but since Buyee only recognized JPY, you need to VPN to somewhere in Japan and used Buyee's Add-to-Cart.
So I guess Tenso is recommended, or any proxy shipping service that gives you a JP mailing address. Buyee is basically Tenso (same parent company), but Buyee will help buy-and-check-the items for you before shipping it, for a small service fee.