Nothing currently in existence gives an ability to creatures with a power or toughness at or above a certain threshold. As such, I can't seem to find anything in the Comp Rules that would give a definitive answer about what happens in the scenario you've given. The closest thing I can find only applies to continuous effects that apply in the same layer, but your example applies in two layers.
Comp Rules wrote:
613.7. Within a layer or sublayer, determining which order effects are applied in is sometimes done
using a dependency system. If a dependency exists, it will override the timestamp system.
613.7a An effect is said to “depend on” another if (a) it’s applied in the same layer (and, if
applicable, sublayer) as the other effect (see rules 613.1 and 613.3); (b) applying the other
would change the text or the existence of the first effect, what it applies to, or what it does to
any of the things it applies to; and (c) neither effect is from a characteristic-defining ability or
both effects are from characteristic-defining abilities. Otherwise, the effect is considered to be
independent of the other effect.
613.7b An effect dependent on one or more other effects waits to apply until just after all of those
effects have been applied. If multiple dependent effects would apply simultaneously in this way,
they’re applied in timestamp order relative to each other. If several dependent effects form a
dependency loop, then this rule is ignored and the effects in the dependency loop are applied in
timestamp order.
613.7c After each effect is applied, the order of remaining effects is reevaluated and may change if
an effect that has not yet been applied becomes dependent on or independent of one or more
other effects that have not yet been applied.
Based on this, I would say that the creature would be a 3/3 with flying.