For some reason, when I go to Appearance > Customise > Design > Primary Colour Option, I am putting the colour code into the box, and it looks fine whilst in the Customiser, but when I publish and then check to the live website to see if anything has changed, the colour of the menu links and slider button is still the default Spacious theme green.
While checking your site, it seems you’re not using our Elementor slider widget so, I think Elementor plugin is not the issue. Rather, I suspect that Autooptimize plugin seems to cause the issue, Can you confirm it by disabling it and check? If that is not the issue, Let me know again.
If you are referring those via the widgets as in demo, then, you can drag and drop the theme provided widgets in the required Front Page sidebar areas available. But, if you are referring to select multiple categories for the same widget then, it is not available in the theme.