Finding genuine antique decks? You’re in for the long haul.
Look up Lady Charlotte Schreiber she was this Victorian collector who spent over 20 years traveling around Europe looking for rare playing cards. Sometimes she’d go years between decent finds. Apparently took her seven years to track down one specific 15th-century deck in Venice.
Pretty much every serious collector I’ve met has been at it for decades. The really rare stuff doesn’t show up often, and when it does, you’d better have deep pockets.