Use Iconpicker on custom configuration block form

Problem/Motivation

I want to use the font icon picker field on a custom form

Proposed resolution

Remaining tasks

Create the form, create the field, used "font_iconpicker" as type but is not working

$form['icon_picker'] = [
        '#type' => 'font_iconpicker',
        '#title' => $this->t('Icono'),
        '#description' => $this->t('Icon'),
        '#default_value' => $config['icon_picker'] ? : '',
    ];

It's my first time trying to reproduce a field provided by a contrib module to a custom form and maybe it is really simple, if you can please, provide some light, that will be great.

I read about field and widget importing but it was on D7 hooks and didn't use them,

Thanks in advance,