FormPage interface works, more or less, as follows:
"Submit" button validates the input and if it is correct it triggers 'body' which is, again roughly,
Dynamic[formfuncion @ input].
Dynamic is a regular preemptive one, restricted by
DynamicEvaluationTimeout to 6 [s]. We need to make it queued (main link)
SynchronousUpdating->False. (lookup queued/preemtive evaluations).
There is no public interface for this so let's inject it to the boxes:
queuedFormPageDisplay = (ToBoxes[#] /. DynamicBox[content___] :> DynamicBox[content, SynchronousUpdating -> False] // RawBoxes) &;
queuedFormPageDisplay @ FormPage[
"country" -> "Country"
, (Pause; GeoGraphics[#country]) &
WolframCloud front end is completely different and Froms are even more special. There are no FE-Kernel links as we know it. So even if there are waiting time restrictions, it is a completely different story. The only issue that you may face is the limitation of your account, in terms of available cloud credits or evaluation time (don't know what is the default limit).