How to remove products-links after the product title using remove_action

First, you’re correct that removing the action calling the products_links method would work, and that this is specifically MrBara_WooCommerce->products_links().

In your functions.php, you can just use remove_action without wrapping it in a function used as a callback for another add_action, btw.

so:
remove_action('products_links, array('MrBara_WooCommerce', 'woocommerce_single_product_summary, 0) 10 is default priority, and while we may assume your priority needs to be higher than the add_action so it is called to remove it after it is included, WP codex notes this:

To remove an action the priority must match the priority with with the
function was originally added.

And

You cannot successfully remove the action before it has been added.

You also cannot remove an action after it has been run.

So, one issue you’re having may be that by hooking an add_action with a default priority (10) to call a function that does the remove action with a 0 priority, is doing so after the action with a zero priority has been run.

Child versus Parent

Since child theme functions.php runs before the parent, you need to hook this after the theme is set up. [wp_loaded]1, [after_setup_theme]1, and init are possible options here.

an example using our earlier back and forth:

function remove_products_links() {
    global $mrbara;
    remove_action('product_links', array($mrbara, 'woocommerce_single_product_summary') );
}

add_action('after_setup_theme', 'remove_products_links');

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original answer

The second argument needs to be an array like so:

remove_action('products_links', array('MrBara_WooCommerce', 'woocommerce_single_product_summary' ) );

To access it from a global variable that holds the class, something like:

global $mrbara;
$mrbara = new MrBara_WooCommerce();
function remove_product_links() {
    global $mrbara;
    remove_action('product_links', array($mrbara, 'woocommerce_single_product_summary') );
}

add_action('woocommerce_single_product_summary', 'remove_products_links');