PHP Query of Summarize Posts in a Widget

I need to build my own PHP based query because I’m filtering dates for my quartet’s upcoming and past shows.

I made a page template successfully using comment #2 from fireproofsocks (thank you!):
https://www.ads-software.com/support/topic/summarize-posts-shortcode-coding-issue?replies=7

Now how to I put a similar chunk of code into a widget? As I can’t filter based on dates with the shortcode alone.

https://www.ads-software.com/plugins/php-code-widget/ ? Or is there a better way?

Thanks for any comments!

https://www.ads-software.com/plugins/custom-content-type-manager/