Add previous / next links to CPT single posts - found support topic 2017

There's probably an efficient way to do this via GenerateBlocks - New Element - Block (? For a function / echo line of php)- Hook
Display on CPT

This isn't working. it's amended from the 2017 post which dragged out to 2020.

Note: I'm using GenerateBlocks the replace the Content Template of the archive CPT pages. Not sure if that screws things up. It's just content thrown in after one hook, yes?

add_action( 'generate_after_entry_content', 'j66co_cpt_showcase_post_nav' );
function j66co_cpt_showcase_post_nav() {
if ( 'showcase' == get_post_type() ) : ?>
<footer class="entry-meta">
<?php generate_entry_meta(); ?>
<?php if ( is_single() ) generate_content_nav( 'nav-below' ); ?>
</footer><!-- .entry-meta -->
<?php endif;
}

add_action( 'generate_after_entry_content', 'j66co_cpt_photography_post_nav' );
function j66co_cpt_photography_post_nav() {
if ( 'showcase' == get_post_type() ) : ?>
<footer class="entry-meta">
<?php generate_entry_meta(); ?>
<?php if ( is_single() ) generate_content_nav( 'nav-below' ); ?>
</footer><!-- .entry-meta -->
<?php endif;
}

https://generatepress.com/forums/topic/nextprevious-post-links-on-cpt/