Why does my tablet often react so slowly, although I almost always have more than 1 GB of RAM left?

Es
2

8 inch Huawei Android tablet, with quad core 1.4 Ghz processor and 2 GB RAM, whereby I actually always have more than 1 GB Ram, so only about 900+ MB are used.

Is it because some programs only access one core and 1.4 Ghz are relatively few?

Ra

Which Android?

Es

Android 7.0