Hi Rasetsukoku,
I may not be fully understanding the question, in which case I apologize in advance. The options to choose a template may be based on your theme. The plugin creates a custom post type, which is neither a post or a page.
Are you using a child theme? If so, and your theme has a page template you like you may be able to copy it from your theme directory to your child theme directory and name it something like ‘single-yada_wiki.php’. I think WordPress will then use that when viewing wiki pages. If that template is not available it will look for ‘single.php’ and if that is not found then it will look for ‘index.php’.
Here is a page that talks about it:
https://codex.www.ads-software.com/Post_Type_Templates
If I’m not focusing on the right question then please provide more info and/or show me the pages on your site and maybe we can figure it out. I don’t think it should be too hard.
Best,
David