That's clearly not normal if it changed all of a sudden. Two or three hours is really short. Games like Genshin Impact are definitely battery hogs, that's true, but there's one thing people often forget to check: whether your screen brightness didn't get turned up without you noticing. Sometimes settings reset to default after a system update, and then boom, brightness goes all the way up on its own. That alone can easily drain 30-40% of your battery.
After that, you should check your battery manager to see exactly what's draining the power. Go into settings, battery, and look at the detailed consumption breakdown. If it's really the games at the top of the list, then there's a problem. It could be a few things: an app running in the background that's slowing down your system (so your phone has to work harder to keep up the game's framerate), a game update that changed something, or straight up a battery that's starting to wear out. If it's the battery, it loses efficiency and your phone drains it faster even with the same workload.
Try first just turning down the brightness to a normal level, even if you have to lower the game quality temporarily. Also force-close unnecessary apps running in the background. If the problem keeps happening after that, you'll have a better idea whether it's really the battery wearing out or some software acting up.