What is the alternative of makeStyles for Material UI v.5

You can still use the makeStyles utils as what you’re using, but in material v5 if you love to do it you need to install one more package @mui/styles and

import { makeStyles } from '@mui/styles';

https://mui.com/guides/migration-v4/#mui-material-styles

The makeStyles JSS utility is no longer exported from @mui/material/styles. You can use @mui/styles/makeStyles instead.

Also, you need to add tab and purple to createTheme if you need them

const theme = createTheme({
  typography: {
    tab: {
      fontSize: 20,
    },
  },
  palette: {
    common: {
      purple: 'purple',
    },
  },
})