Remember, online research is The Internet. You won't get the kind of accurate diagnostic that you or someone else would do in person.
Factory amps should have no parasitic drain when the vehicle is off, or at most some trivial low level sensing that wouldn't drain the battery in weeks. If this is an aftermarket install done by a cowboy, who knows!
The way to troubleshoot this is grab a multimeter, a couple alligator claw probe tips, and put it in series with the battery to measure current when the vehicle is off. When you disconnect the battery to do this, you want to have the multimeter probes already in contact with the battery cable and battery terminal so it does not cycle from battery disconnected to battery connected again through the multimeter, which may reset the battery saver timer to start counting down again for some time period before going into low power state. For other Ford vehicles around this era, I vaguely recall that the power saver time-out period was something like 40 minutes (at least a half hour but less than an hour I am certain of for other Fords with the battery saver circuit), but this too can be tested with a multimeter if, or once, everything is working right again. Ironic that a "battery saver" circuit causes higher battery drain. Progress?
Now, it may have random things like courtesy lights or whatever, that put the vehicle in a higher power state for some period of time after it is triggered. For example, merely opening the door to reach in and pop the hood release, might put it in a 200mA+ drain mode that doesn't settle down to tens of mA for over a half hour, and this is completely normal. On the other hand, a failed relay that handles the battery saver circuit can cause it to continue to drain at 200mA+ indefinitely.
With a multimeter in series you would pull out each fuse and relay in turn to see which change the current, narrowing it down to what is on that circuit.
IF it were that the amp is wired wrong to get constant battery current, that might be redone correctly. It is not the case that everyone with an aux amp has their battery go flat in 3 days. This can be fixed "somehow", the question is if the right person sees the right info to know what is going wrong.