On Thursday, April 9, 2020 at 3:31:56 AM UTC-4, wrote:
...what if there's a shared software bug between the parallel systems,
like the firmware bug triggered by date that affected many GPS's simultaneously.

That wasn't a bug, epoch wrap was well understood and not implemented
by everyone. Especially in consumer stuff expected not to last 1 epoch.

It'd be safer to combine two completely different systems for maximum
redundancy, like Igor's MiniLAK FES-Jet (https://imgur.com/a/Y6uK4fP)

Pretty much guaranteeing something will always be broken,
and doubling the expertise required to diagnose and fix...