Thank you for this!

I always feel ashamed to have to ask how to do what I imagine is pretty elementary stuff for regular Linux users, but now I feel kind of feel dumb for not just asking in the first place.

customizing the default Plasma Panel (right click on desktop > enter edit mode > add panel) is your best bet nowadays for a similar look

This will be more than enough for me. I was looking for latte-dock because I thought it was the only way to accomplish that look.