Hot Take: play them backwards. I think 4 is the simplest and more straightforward and just looks real fucking nice. From there if you like 4 you can keep going backwards. Even the 1 and 2 are pretty good. But the further back you go the more rough around the edges they are. But even if you really like old school NES RPGs I think playing them backwards is still the most fun. 3 might be the best but 4 is a pretty straightforward enjoyable play through. And then 1 and 2 are pretty good if you like old style JRPGs or just really like the series after having played 4 and 3.