How can I get the standard WP-Editor through Javascript?

Ok I found the solution here

Just do

wp.editor.initialize('editor_id', {
    tinymce: true,
    quicktags: true
});

And then add buttons to the toolbar like so:

jQuery( document ).on( 'tinymce-editor-setup', function( event, editor ) {
    if(editor.id !== 'editor_id') return;

    editor.settings.toolbar1 += ',mybutton,alignleft,aligncenter,alignright,fontselect,hr';

    editor.addButton( 'mybutton', {
        text: 'My button',
        icon: false,
        onclick: function () {
            editor.insertContent("It's my button!");
        }
    });
});

It only works with jQuery as I understand because it’s a special function added to jQuery by WordPress (in WP 4.8+).

You can see all possible toolbar buttons here: https://www.tiny.cloud/docs/advanced/editor-control-identifiers/#toolbarcontrols