>>14029362If you wanna start with the purest games that just contain the core gameplay of the series start with the Arland games(Rorona, Totori, Meruru) and Lulua. Their alchemy systems are simple and an easy introduction.
The Dusk series is also pretty good but I can't say anything since I haven't played them personally yet.Sophie and its sequels(Firis and Lyride&Suelle and eventually Sophie 2 next year) attempted to introduce a kind of minigame in the alchemy system to make it more fun but some people didn't like that or felt it deviated too much.
Ryza and its sequel are the most modernized games with mechanics to make progression a lot faster and simplify a lot of stuff but they're overall very good games and add new stuff that will probably be used in future games.
Pretty much all the games have similar themes and stories as well so you wouldn't miss much if you skipped ahead to Ryza and went back to the older games after. Just pick whichever series has your favorite girls desu.
You might miss some cameos of characters from the older games if you do that but since each series takes place in a different world the cameos aren't really relevant to the story. 