MUI - Premium Data Grid toolbar icons are not appearing properly

Question

I want to do three things -

1. Correct the display
2. Putting custom icons for the toolbar item
3. Add a custom toolbar option.

This is how I am using Datagrid.
  <Grid item xs={12}>
    <DataGridPremium
      columns={columns}
      rows={rows}
      slots={{ toolbar: GridToolbar }}
      components={{
        Toolbar: GridToolbar,
      }}
      autoHeight
      checkboxSelection
    />
  </Grid>