With modern smartphones, with the right options, that's going to be rather typical.

There is usually some setting to limit charging to 80%, and while it depends on your model and usage, going down from 80% to 30% at the end of the day is quite typical. Then you can charge overnight (preferably using slow charging) back to 80%.

But when you need it (ex: travel), you have the option to unlock full charge and use fast charging.