I really would like to understand the difference between Car GPS and Trecking GPS. Are they similar?

I mean here from the point of syncing with satellites. I saw some trecking GPS that sync with 12 ( 12 channels). Does that mean that they are more sensitive than Car GPS?

Is it possible to use car GPS for trecking
Or are there GPS that can be used for both applications at the same time, and may be also for sailing, let’s say
If they are identical hardware-wise, does that mean one can use maps files for cars on a trecking GPS, or vice-versa?

Thank you in advance.