The safest and most reliable way to obtain the game is through official digital storefronts. Depending on your region and preference for content (All-ages vs. R18+), you have several options:
If you have a large collection of mods and DLC from original COM3D2, you will need an additional 20-50 GB of space.
You can purchase the base game, Custom Order Maid 3D2 It's a Night Magic , and the COM3D2.5 + X0 Upgrade directly. Note that the Steam version is "All-ages" by default but can be patched for adult content via official supplement patches.
expansion), existing owners of the original game may need to use specific DLC copy tools