Footer Widget on full wide

Hello!
I like the Theme mesocolumn very well and I would like to have no other. As often, however, a good theme has to be adapted.

What I want:
Instead of four Footer widget area I would just like one Footer widget area that goes across the whole page width (without the sidebar – which remains right next to it). I have done so far. The widget is called “Test”, but this does not have the whole page width. It should be as broad as the content (without the sidebar).

I’d like to paste into the Right Sidebar widgets, but then the Tabbed Sidebar disappears. Is it wanted like that? It would be nice if one could still insert widgets under the tabs, which are not as tab (for example pictures or feeds)

Then I have one more wish: In the Category Archives I have set Magazine Style. This is good for most archives, but the Category Archive “Chronik” (https://zeit-am-meer.de/chronik) is not good. I would like the contributions all complete, uncut and without excercpts. Is that possible? Although the length of the excercpts can be adjusted, only long excerpts, but not the whole text, are displayed even at 99999.

It would be nice if you could help me to implement my ideas. If that succeeds, I am also willing to donate something.

Translated with Google – sorry ??