Not only the Genshin impact drain the laptop battery but all the other highly graphics intensive games you play will drain your battery and in a short time you will need a new battery for your laptop.
Gaming laptops very expensive laptops have good batteries but when playing the latest games they give backup to 1 or 1.5 hours of battery time because the batteries they have not designed to give backup on laptop full performance,
you will notice that most of the laptops requires you to plug in the laptop so then you will be able to use the full performance otherwise the laptops locks itself to normal performance like it uses builtin gpu.
How to stop Genshin impact / Sims 4 not drain laptop battery
You should keep your laptop plugged in while gaming or doing other high energy using tasks, also check what is the difference between Sims 4 Laptop Mode vs No Laptop Mode.
But if you wish to use the battery then it is best to lower the game resolution or lower the graphics mode so this will not only give you more battery backup but also slow power draw will save your laptop battery from getting dead early.