A Pokemon Legends: Arceus Poke Ball replica figure is available in the Pokemon Center. It costs $69.99. According to the product description, the material is resin, and it has recreated the look of the wooden base and the metallic trim. This is only for decorative purposes. You cannot open up the Poke Ball.
The Pokemon Legends: Arceus Poke Ball replica will come with a display stand. It is around three inches in diameter, which makes it the right size to place around your house or apartment. It states that there is a purchase limit of two. However, it does not state if this accounts for each customer or each household.
Here are some pictures of the Poke Ball replica figure:
In Pokemon Legends: Arceus, which takes place in the Sinnoh region of the past, trainers have to actually construct their own Poke Balls. The mechanism of the ball itself is the same as more “modern” Pokemon games, but the design is obviously different. For one thing, it appears to have a latch of sorts on the front, whereas newer Poke Balls have a button.
Pokemon Legends: Arceus is readily available for the Nintendo Switch. You can purchase the Poke Ball replica from the online Pokemon Center shop.