Houkai Gakuen 2 is a great gacha game, you can get far just with monthly passes and saving crystals just for extremely good gacha banners.
From time to time, extremely good value for money items are added to the cash store, so if you are interested in ranking events and want to reach veteran performance, it is recommended to buy these items to speed up your progress in the game so as not to get discouraged and quit the game.
The game is not as popular as other Hoyoverse games due to lack of advertising from the company itself, but I'm sure it's the best game among them all because the game has beautiful graphics and rich gameplay.
To conclude, I will give my opinion with my positive and negative points regarding the game.
good points: the game now has a great newbie banner, so new accounts can start very well equipped from the beginning and reroll can be done before registering their permanent account easily.
bad points: it is impossible to complete builds and participate in ranking events without spending money on this game, unless you have the patience to play for several years, but at this point, the game may even announce end of service (eos) before you finish your setups. So if you want to play with quality of life now, keep in mind that you will have to spend on monthly passes and if you want to improve, sometimes on battle passes (bp) and promotional items.
The fanbase for this game is limited and dispersed across the internet between discord and x (twitter) channels, so look for groups to talk about the game if you are interested. There are Japanese and foreign communities, so you can communicate in the groups you prefer.