Considering you mention having registered a custom taxonomy instead of using the native tags, the functions the_tags()
and get_tags
will not work.
you need to get your custom taxonomy terms by using get_the terms()
. Usage is not much different from using native tags, but you have to pass the post_type as a variable.
See the WordPress codex on this: https://developer.wordpress.org/reference/functions/get_the_terms/