Hi Chris,
In terms of PDF export via the Report Builder - We have a certain number of users who already requested this and our developers are working on it.
I can't say an exact ETA, but they are doing their best to finish it as soon as possible.

You can upvote that feature here : https://features.wpdatatables.com/111.

- Now, what you suggested here is interesting, perhaps it is slightly different than what we originally were working on, to have the template as XLS or DOCX, but only export it as PDF in the end.
I am honestly not 100% sure exactly which functionalities the devs are 'cooking up' for the PDF export via Report Builder, but, you can certainly add your version of this development suggestion as a new Feature suggestion on that Page : https://features.wpdatatables.com/.

So our devs will go through it - and if it's already the same as they are working on, then they will just 'merge' both requests together as one;
Or if yours is different, they can add an additional task for this option. :)

I certainly like this idea for a use case, it would be very useful for that scenario, as you described.

As more people vote, the feature will move higher on the priority list.

We can't say an exact ETA, but you can certainly follow our changeLog page if you'd like ( it is also available in the plugin dashboard), where we state any changes/new features/bug fixes during updates;

and our newsletter, so you're informed about new features, bug fixes, freebies, etc.