Provide template paths by filter

other-plugin.php

<?php
add_filter("my_plugin_add_template_paths", function($paths){
    $paths[] = plugin_file_path(__FILE__)."/my-templates-dir/";
    return $paths;
});

Templates.php

<?php
namespace PublicFunctionOrg\WordPress;
class Templates {
    public function get_template_path($template){
        $paths = apply_filters("my_plugin_add_template_paths", []);
        foreach ($paths as $path){
            if(is_file("$path/$template")){
                return "$path/$template";
            }
        }
        return false;
    }
}

// find templates 
$templates = new Templates();
$filepath = $templates->get_template_path("my-template.php");