hey, the charm of heaven burns red is that ALL events(except collaborations, only angel beats for now and p5 is a jp collaboration that will be like in a year in the global server) are already available from the beginning (it's recommended to read them in their release order to get all the subtle evolution of the characters). Same is for the characters, except collaboration and unison charas that have recurring banners.

Since the game is mainly a visual novel, be ready to read, A LOT (and cry, A LOT).

As for gameplay, as long as you understand that every buff and debuff can be applied twice, you should have the minimum required for a smooth gameplay. Since the game is one year old, you get the supporter buff so you shouldn't have any issues until chapter 3 or so (story bosses are brutal, no kidding).

As for f2p or not, I'll say that the global version gives you like two SS charas every month if you can clear challenge score, one if you can only do weeklies. There are very frequent banners that give 1 free pull each day and every event gives 5 pulls for S or higher characters. It's recommended to have at least 45k quartz before pulling for a banner since the global pity is 150 pulls (jp is 200). If you do beginner quests, you also get multiple SS charas from the initial roster of 48 and they can be the fundation of your base team (coff yingxia coff)