I own but haven't played the Life is Strange games yet, but I enjoyed Tell Me Why and am looking forward to this.
Is it necessary to play past LiS 1 to enjoy the story for this one? I keep hearing LiS2 isn't that great.
Life Is Strange 2 is not connected to the other games, so you can most likely skip it unless this game decides to do something with it but I doubt it.
This game is made by Deck Nine, the people who made Before The Storm, which was a prequel to the original, and with True Colors they're following what they created in Before The Storm.
So if you want the whole thing, I think you only need to play before the storm and LiS 1, or maybe even just Before The Storm, I don't know if True Colors will mention events from LiS 1, I only know that it features character from Before The Storm.
What I would recommend is playing Before The Storm first, it's not very long, it's great, and if you like it you will probably want to play LiS 1 to know the rest, and if you didn't like it, you will know the series is not for you and you wouldn't have wasted too much time. And it's in my opinion a lot better to play this one before LiS 1, as it makes the story in LiS 1 a lot more impactful, I wish I played them in that order, but before the storm came out after so...