My knowledge is only anecdotal. My job used to be to build test fixtures, engineering experiments, and prototypes with no instructions except anything from real schematics to chicken scratch bar napkins. Our department was expected to know how to build power distribution with zero instructions. Circuits could be anything from pure digital to pure analog or more often a mix.
Loopy grounds don't care if they're screwing up an AC or a DC voltage, or an analog or digital signal.
You mentioned ESC specifically. The black wire from the FC to the ESC is less of a 'ground' than it is a reference for the signal. It happens to be called ground but could just as easily be called reference to avoid confusion with other grounds. Since the signal originates from the FC that's where the reference should originate. That's most convenient and accurate because multiple similar design ESCs would prefer to use the same reference. If there's a problem it's be easier to scope and troubleshoot if all ESC grounds (references) are commoned at the same point on the FC rather than, for instance, the ESC grounds be commoned at the battery ground point, or different ESC 'grounds' being connected back to the FC ground through different paths. It probably -could- work that way but that'd be unnecessary weird wiring.
You mentioned 'all devices.' Grounds should be commoned for devices that talk to each other, again so they have a common reference. That's why for example it's best and most convenient to connect power and ground wires from the FC to the Rx. Again it'd 'probably' work if the FC and Rx have separate power/ground connections to the battery or ESC +V (or whatever other source) but that's wasted more complicated unnecessary wiring.
Related to that for example a video system has no interest or relation to Rx or FC. Power and ground can come from anywhere convenient of appropriate voltage. However the camera and VTx components -need- to have a common reference or they'll either get weird or not work at all. Hmmm... an exception to that would be if a noisy video system dumps spikes into Rx or FC power distribution. In that case it'd be better to connect power/ground further back to the original battery source. Or do like I do which is to use a completely separate aux battery that has *no* common connections with the flight system stuff. It's a little extra weight but I don't have to think at all about loops or noise or whatever
I don't know what you really mean by 'no matter how many.'
What's your specific concern/interest?