I own a 2023 Toyota Tundra (1794 Edition) and it has a quasi-infotainment system. The system offers Apple-Play, which is what I use most of the time. I have messed around with the tuner somewhat. Unfortunately, there isn't any capability to tune up and down each frequency of the bands. Your only option is to "scan" up and down the bands. When it locks onto a station you can select that station as a favorite and it will throw the logo of the station on the display screen as an icon. You can do this for AM and FM and the icons are visible on the screen simultaneously. So, just by selecting an icon you can go from an FM station to an AM station. Perhaps someone that knows better than I may have figured out how to actually tune each frequency, but so far, all I have been able to find is scan up and down the band. I will say the sound of the tuner in this system is quite good, especially in HD and the sensitivity and selectivity is not too bad either. I'm pleased with it but Just find it weird you have to scan the bands.
As for HD AM. I didn't even know that was a thing. I've listen to HD-FM often but one day about a year ago I was near Schenectady, NY when I drove past WGY-AM's tower. I selected the station and it went into HD! The HD signal sounded slightly better than the analog, but it's a talk station so not much there to really determine if the difference between the analog and HD are of any significance.