Hello @stadperfekt,
Thank you for your query and we are so sorry about the trouble this must have caused.
We checked your site from our end and we do see a different description. See this screenshot here: https://i.rankmath.com/i/xcE6ur
Please note that it is a pretty common thing with Google these days. It happens with 70% of the results that even if everything’s fine, Google decides to show a different meta information for your search keyword, there is nothing you can do as Google sometimes ignores the custom meta info altogether and show something from the page’s content that matches the search intent better.
To understand more about this, please check this article: https://rankmath.com/kb/different-meta-title-and-description/
As for the sitename, Google uses a machine learning algorithm to generate the sitename for your pages based on other information it has collected about your website and your industry.
We would suggest keeping mentioning the desired title on both the title of the page and the schema structure (which our plugin automatically adds after configuring the Local SEO settings in Rank Math > Titles & Meta).
Lastly, please go through the Google guidelines about the site name to help you increase the chances of displaying the desired site name on the SERP: https://developers.google.com/search/docs/appearance/site-names
Hope that helps and please do not hesitate to let us know if you need our assistance with anything else.