Dynamic Parameter after URL "?s="

Hi Support-Team,
i have bought 6 times your theme for me and clients.
i have analyzed URLs of my clients with my professional seo-software.
And at all pages, i have the original url path and a duplicate path with additional dynamic url sub-code with “?s=”.
I think, the search button is also indexable or it’s a problem around search button?
On the one hand, this is duplicate content. Both URLS are available. This is not good and google will penalize duplicate content.
On the next hand, dynamic urls are not preferred by google.
“URLs that contain dynamic characters like “?”, “_” and parameters are not user-friendly, while they are not descriptive and are harder to memorize. To increase your pages’ chances to rank, it’s best to setup dynamic URLs so that they would be descriptive and include keywords, not numbers in parameters. As Google Webmaster Guidelines state, “URLs should be clean coded for best practice, and not contain dynamic characters.”
The third is, this pages have also a canocial tag.
The fourth is: I have massive duplicate titles and meta dscriptions etc.
The fifth is, i have now the double amount of pages on my site which have errors in HTML and CSS markup.
And the Last: This pages with the additional code are restricted from indexing but vissible for google bot.
Please take this urgent into account and repair this. I have some trouble and some rankings are fallen.
I track the ranking with my seo-software and i can see an impact.

Cheers

Arne