For the best experience, search for the "Paprium Complete Preservation Project" on the Internet Archive. Look for the December 2023 repack, which includes the manual scans and the input lag patch.
For a to exist, the crackers had to do more than just copy files; they had to reverse-engineer a piece of hardware that was never documented. Paprium Rom Archive
If you own the physical cartridge and have managed to back it up (creating your own personal archive), you may find it difficult to play: For the best experience, search for the "Paprium