[NSFW] overall site width

Hey guys, For a few months by now I want to change the overall site width of my WordPress theme (twenty twenty-one).
After reading some help topics I saw that it must be possible to choose a full-width template in the editor on the right side when you edit the page.
There is supposed to be an option to change the template, but in my case, there is no such option, only slider revolution?
Anyone an idea how i can fix that ?
thx
Johny

• This topic was modified 3 years, 3 months ago by James Huff. Reason: link marked not safe for work

The page I need help with: [log in to see the link]