But I am biased towards Edgeypoo
The overall gameplay is really similar to the main series. The things that set AAI and sequel to the main ones are the lack of Magatama (for obvious reasons) and we have logic thinking for that, as well as the additional logic chess in the sequel. Secondly, you control Miles like an RPG character instead of a novel-like experience. Difficulty wise, AAI is on par with the very first AA title, while AAI2 is as difficult as AA3 and has one of the longest cases! If you're curious or care about the plot, you might wanna give Investigations a try!
Have you played Apollo Justice before? It is the fourth in series, an Ace Attorney DS game released 9 years ago.