No new "Boku no Pico" OVA was produced in 2021, as the third episode, "Pico x Coco x Chico," was originally released in 2008. The 2021 confusion stems from internet memes, 2019 HD remasters, and the re-uploading of the existing 2006–2008 series on various platforms. For more details on the original release, see the Wikipedia entry for Boku no Pico .
The "2021" date you're seeing might refer to one of the following: Internet Hoaxes: boku no pico ova 3 2021