There are two template functions exposed by the plugin - get_template_part_args and get_template_part_vars. The former is used in place of get_template_part, i.e. to pass the arguments and the latter is used to retrieve them in the template partial.

Here's an example:

// Anywhere in your theme templates
get_template_part_args( 'template', 'part', [ 'example_argument' => true ] );

// in template-part.php

// define defaults
$defaults = [
	'example_argument' => false,
];

// combine defaults with passed args
$args = wp_parse_args( get_template_part_vars( $this ), $defaults );