Hello NeuroSaber,
Thanks for writing in!
Because what you are trying to accomplish requires a template customization, we would highly to suggest that you use a child theme. This allows you to make code changes that won’t be overwritten when an X update is released.
After the child theme is set up, please add the following code in your child theme’s functions.php file
// Add Gutenberg Support to Portfolio items
// =============================================================================
function x_portfolio_gutenberg($args){
$args['show_in_rest'] = true;
return $args;
}
add_filter('portfolioposttype_args', 'x_portfolio_gutenberg');
// =============================================================================
We would love to know if this has worked for you. Thank you.