Hello, @samjazaerli,
Thank you for providing a detailed explanation. I regret to inform you that utilizing a demo in the current manner is not considered an optimal approach. Allow me to clarify the reasons behind this.
Each demo is designed with its own distinctive styling, layout, and content. When running the demo import process, not only does it import the desired content, but it also overwrites the existing content on the site. This step is crucial for successfully importing the demo, as it is a standardized procedure followed by every theme.
Fortunately, I have a solution for the issue you are facing. Firstly, you need to export your site content, including products, media, pages, and posts, using a third-party plugin of your choice. Once this export is complete, attempt to import the demo onto the site. Once the demo is successfully imported, you can proceed to import the previously exported content back onto the site.
I trust that this explanation clarifies the steps required. Should you have any further questions or concerns, please do not hesitate to reach out.
Best Regards,
PThemes Team.