I played a bit of Marie + Elie on PS2 and found it really nice.

I just started Atelier Firis yesterday, so let me share with you the things I've gathered:

The first 2 games of the Dusk trilogy have time limits, which isn't great for a beginner trying to figure out the game mechanics. In the mysterious trilogy there's only Firis with a time limit until the exams (and it's supposedly a pretty generous one). After that you can chill again for the rest of the game. So, I'd recommend starting with Sophie and then the rest of the mysterious trilogy, followed by Sophie 2.

And then there's also the Ryza games, which people also call beginner-friendly, for those that want a more action-based gameplay.

my partner made fun of me cause i was pronouncing atelier as "a-tel-lie-er" which i now realise is not right

Barrel!