So from the research I have done into this I’ve found out the follow:
To display the Text as a Link, without the Post Title but within the same category you would use the follow
<?php next_post_link( '%link', 'Next post in category', TRUE ); ?>
To do it with the same custom taxonomy the following applies
<?php next_post_link( '%link', 'Next post in taxonomy', TRUE, '', 'my_custom_taxonomy' ); ?>
I’m sure by looking into next_post_link and previous_post_link you will be able to find a way to link the links with your custom field.
Best of luck 🙂