>>57787446Default answer is the latest one because that and a few of the previous games are going to be the easiest to find on sale. The current one being Yumia.
The games usually have 3 titles set in the same game world and the currently available series (in order) are: Arland, Dusk, Mysterious, Ryza, and Yumia/Memories. Across all of them, you play as a young woman learning alchemy (item crafting) and have some kind of self discovery story where they learn to become more dependable, usually mentoring the following game's protagonist. The general gameplay loop is to go out, collect items at gathering spots, return to the Atelier to build more items, then use items to advance the story, or blow up enemies with the items .
Arland and Dusk are based on an older gameplay style where every action has a time cost, and if you take too long to do something you could miss out on an event and there's heavy emphasis on replaying for different endings. Alchemy is a known skill in those worlds, and the player characters are younger with more of a fantasy frilly outfit.
The most recent Ryza and Yumia series are open world without any kind of time constraint, and there's more focus on adventuring and active battles. The job of Alchemist isn't really known or even taboo and in general the characters are older, opting for a more modern fashion.
Mysterious is a midway point between the two. The time constraints are gone, but for most of the series the maps are setup like the older games where you go to a gathering area then return home to make things. Battles are turn based and the characters are still younger in frilly outfits.