Support

Of course you can. Akeeba SocialLogin simply uses Joomla 4's additional login buttons feature. This is a feature I had contributed myself about 5 years ago, to end the awkward tendency of every login method developer that doesn't rely on just a username and password to invent our own hack-ish method to show our login buttons. Now there is a standard in core Joomla.

All you have to do as a login form developer to consume this API is to use Joomla's helper static method, \Joomla\CMS\Helper\AuthenticationHelper::getLoginButtons() and render its results. Do remember to pass your login form's id attribute value as the sole parameter to this helper method; it's required for additional login buttons to work properly.

You can see how to render the results in modules/mod_login/tmpl/default.php, namely the block that starts with <?php foreach ($extraButtons as $button) :. The $extraButtons variable is simply the result of calling the helper method.

Yep, you definitely need the FORM tag's id attribute to do that. You may want to reach out to the form component's developer to see if there is a way to get that information programmatically. From that point it's easy; it's just what I explained above.