I think @Nigel said they last around 5 years, by that time you most likely want to replace the camera due to advancements in image quality.
I don't think I've ever given a time for an RTC battery, I don't know how long they typically last, but I would consider 5 years to be too short.
If used at normal room temperature then I would expect the Viofo ones to last maybe 20 years, but in the heat of a car, I would hope for 10 years before you started loosing the time, given that the car is driven more than once per week (they are rechargeable).
We do hear of failures on some cameras only a few years old, but normally on specific cameras models and only on a small number of cameras, so I assume some quality issues with the batteries themselves, maybe also heat related, and certain cameras could have been designed better.
Those green things are super capacitors.
Yes, the RTC battery is silver.
So far, I have not been able to find a single camera that would work at over 60-65C, regardless of whether it is with a capacitor or a battery.
I am not sure what those temperatures you are quoting mean, are they outdoor temperature, as given by the weather forecast, car internal temperature, dashcam surface temperature, dashcam internal temperature?
If they are car internal temperatures then they don't mean much because on a hot day there is a big difference between seat height temperature and mirror height temperature, and the result will depend a lot on how reflective your windscreen is to UV and IR light.
I might assume that they are the oven temperatures that the dashcam has been tested at, except I know that some manufacturers test a lot hotter than the temperatures given in the specifications.
In reality, dashcams with super capacitors are designed and tested to be left on the windscreen in all conditions and most work fine for many years, while dashcams with batteries are designed knowing that their battery will fail after around 18 months, unless they are demounted on hot days, and normally with the company selling them being very happy to sell you a replacement, or refurbished unit when they do fail! Some companies make the batteries easily replaceable, most don't.
For very hot places, we do not recommend battery dashcams, for cool places we also don't recommend them, but at least then they may last several years.
RTC batteries are generally not a problem.