Should I interlink my city landing pages with my homepage?

Let's say I own plumbers(dot)com with multiple locations and I have created a separate landing page for each city that I want to target.

If I build backlinks to my homepage, will my city landing pages automatically rank higher as well or do I need to build backlinks to those landing pages separately?

Do I need to interlink my landing pages with my homepage so the link juice passes from the homepage to those landing pages or is that unnecessary?