I’m an electrical engineer. I just want to explain the hazard with panels.
They are DC, and the voltage is usually very high, between 300V and 600V.
At this voltage you will get a burn, like touching a hot kettle, but because it is DC you will be able to easily “untouch” it.
Yes, the panel frames should all be grounded to each other, and also to Earth in one spot along the chain, as this makes it more difficult to be electrocuted by them because the resistance of the grounding wire is much lower than the resistance of your body, and electricity takes the shortest path.
I was just pointing out that a solar installation with only an inverter and no transformer does not need a separate ground since it’s not a separately derived system. An auxiliary/supplementary ground rod is allowed by the NEC (250.54) but it is not required.