For example, on my single product page, there’s no way to go back to the main shop page. I’d also like to add a link like that to the cart and checkout pages. Any suggestions?
Regretfully this isn’t a feature offered by X. It could be possible with custom development, but this would be outside the scope of support we can offer. You may wish to consult a developer to assist you with this. X is quite extensible with child themes, so there are plenty of possibilities.