Graham tiaxgame _xtgem_templates is not required in the path it is pre-configured and fixed
you only need to add a folder if it is a sub folder of _xtgem_templates
ie:
if the file is _xtgem_templates/macros/macro_1.twig
You would use {% include 'macros/macro_1.twig' %}

if the file is _xtgem_templates/macro_1.twig
you just use{% include 'macro_1.twig' %}