I've been quite impressed with the navigation in my 2018. It works far better than the built-in NAV I've used in any other car. No, it's not as good as WAZE. Fortunately if that's needed Android Auto is right there. My biggest complaint about using Android Auto is that Hyundai decided to underpower that USB port so the phone will barely charge.
I've had HD Traffic reroute me occasionally due to traffic. I've also had a pop up saying traffic has changed, we now have a shorter route, would you like to use this faster route? I can't compare to SiriusXM traffic. When I had the free trial the NAV still typically showed it was using HD traffic. If I really want to be sure I'm taking the best route considering traffic I'll fire up WAZE on the phone and compare to the built in NAV. Most of the time they match up so I don't bother using WAZE.
I've never seen a pop up about needing a subscription except when the trial was about to expire.