errors in search console data Structure report

Hi!
I am not a code person. I am a beginner.
There are some errors on structured data in my google search console file for my website: https://wasterush.info/
The structured data errors are already rather old and left over from after I started some SEO, but before I installed Yoast SEO plugin. I have not been able to find instructions to fix them.
So I went to Google Webmaster forum for help, and the second time I tried them my helper sent me some very interesting things…as he also could not just offer me instructions. He believes that the errors are from my theme. “Note that everything I have read about this issue with wordpress themes is that several themes just don’t support the markup properly at this point in time. Also, I see that this error in itself is not really going to be harmful to your site’s ranking ability.  So, not a big issue, though of course it would be nice to not have to deal with those errors.”

My theme is Twenty Seventeen.

Yoast is pointing to my theme as the problem. https://kb.yoast.com/kb/fixing-hcard-author-error/
And it looks like WP knows about it. https://wordpress.org/support/topic/structured-data-hentry-markup-microformats-org-2/
The guy in this thread found a plugin to fix the problem. You can see it at the end of his thread. It is
https://www.acceleratormarketing.com/product/fix-structured-data-errors-wordpress-plugin/
I looked for this plugin in the wp.ORG plugin directory and did not find it. The plugin page says it fixes these issues in the theme. I hesitate to use it.

I wonder if there is another way to fix these problems. If I knew how to delete the markups I did, maybe that would do it….but maybe it is not the structured data that I setup, maybe it is the theme?????

Do you know about this problem? Do you know what I can do to clean up my site on G. search console?

I have screen shots that I can send you from the structured data.