Got hooked by the "Taiko Quest" and the dungeon!

I've been interested in the illustrations for a while, and thought, "Why not!" so I gave it a try. The art is beautiful. The music is beautiful too. I'm hooked... I want to keep playing, but I'm worried it might turn into a "gacha hell" if I'm not careful. I hope I can stick to being a light spender. I'll observe the hidden quests a bit more before deciding. If I feel confident I won't get too addicted, I might consider continuing.