Preview links don't work from Gutenberg for drafts

[iakshay]

Describe the bug
Preview links don't work from Gutenberg for drafts –

This seems to be a problem in upstream WordPress/gutenberg#13998. Not sure, whats a good short-term solution for this. Would be nice if this can be fixed.

I was thinking something like this might work in index.php -

if (is_user_logged_in() && $_GET['p'] && $_GET['preview']) {
    $post = get_post($_GET['p']);
    header( 'Location:' . get_preview_post_link($post), true, 303 );    
} else {
    header( 'Location:' . HEADLESS_FRONTEND_URL, true, 303 );
}

To Reproduce
Steps to reproduce the behavior:

1. Create a new post from admin UI, type in the title and content.
2. Click preview as in the screenshot above, the link points to Wordpress rather than NextJS website.

Expected behavior
The preview link points to Wordpress and redirects to NextJS home page rather than post preview.

Screenshots
Attached above