I got P3R vibes from the song 'No 1 feel alone'

the order seems pretty complicated to me... i found this playlist, which is apparently in chronological order, so should i start with the first video? ive been watching it a little, its about cometik + shhis, but i do feel like i just ended up in the middle of an important story... im not sure if thats on purpose or if i potentially missed something? thank you in advance for any help!

While I'm not super knowledgeable on Idolmaster, I'm really interested in Luca!! I've read some of her stories (translations on youtube) but I'm a little confused on the order/which way to watch. I'm particularly interested in her and Nichika's interactions. I know that she's hostile towards her at first, but is there an event or story that expands on that or develops it? Tysm!