There are a number of plugins that let you add stuff to the header. For example, see https://kinsta.com/knowledgebase/add-code-wordpress-header-footer/

For more of a “roll your own” approach, see https://developer.www.ads-software.com/reference/functions/wp_enqueue_script/

You could use a conditional filter to decide if you want to put the script on the current page or create a custom template and select that for map pages.

Thanks, I’ll check your other links.