This is not possible, because the collection object only works when you go to the collection page page. So when on home page and show collection page, it won't work.
You can just use JS so that when the customer goes to the home page, they will be automatically redirected to the collection page.
Ex: window.open('link', '_parent');
Yes you can add code in theme.liquid file:
// collection/all can be changed to the link collection you want, ex: collection/abc