Hello,
Header areas full width you can disable in the Header builder settings https://prnt.sc/1t8k7sz
You can change bg size using Revolution slider settings https://gyazo.com/cce399dbc28d2f8424de5405c0d5b9f0
If you want to get categories with the subcategories you can manage that from Products > Categories > edit categories and choose the Parent category.
To add widgets to the shop sidebar go to Appearance > Widgets > add the necessary widgets like Price filter, brands filter etc to the Shop sidebar widget area.
Regards