Problem with a page loaded by a plugin

I have a plugin which integrates a page in wordpress. This page has some code and the header and footer. Its called by the plugin and is not physically present at the pages table in wordpress.

Problem: The page look slightly different then the other pages. The color is different in some areas, the font and also the menu doesnt show all the parts like it does on the other pages from wordpress.
For testing I deleted all code from this page and just leave it with calling the header with get_header() and the footer with get_footer(). But this doesnt fix it.

Theme change doesnt fix the problem either.

I checked the CSS from the plugin page with a “normal” page. At the “normal” page the color for an element is defined with
.elementor-107 .elementor-element.elementor-element-950563d {
color: var(–e-global-color-text);
}

But when I look at the same selector at the plugin’s page it says “–e-global-color-text is not defined”.

Does this page still need other template parts to show up correctly?