Fact: quantization of gravity is still at a research stage, only effective quantized field theories are used.
Fact:gravastars ( had to look it up) belong to one proposal for quantizing gravity, which is not particularly dominant in the research .
A gravastar is an object hypothesized in astrophysics as an alternative to the black hole theory by Pawel O. Mazur and Emil Mottola. It results from assuming real, physical limitations on the formation of black holes. These limits, such as discrete length and time quanta (chronon), were not known to exist when black holes were originally theorized, so the concept of a gravastar is an attempt to "modernize" the theory by incorporating quantum mechanics. The term "gravastar" is a portmanteau of the words "Gravitational Vacuum Star".
Chronons belong to this specific hypothesis for replacing black holes by a quantum mechanical equivalent, and this is the first time I met them, though a particle physicist.
So, it seems reasonable to wonder if black holes are distinguishable from gravastars since gravastars appear to be better emitters, and black holes better entropy sinks.
is comparing apples with oranges. Black holes come from classical General Relativity. Gravastars belong to a model of quantized general relativity.
(The application of quantum field theory at the horizon of a black hole giving Hawking raditaion, does not turn the black hole from a classical singularity to a quantized gravitational one.)
String theories allow for quantized gravity and at the same time can embed the standard model of particle physics.
There is a string theory based model which turns black holes to fuzzballs.
Fuzzball theory replaces the singularity at the heart of a black hole by positing that the entire region within the black hole’s event horizon is actually a ball of strings, which are advanced as the ultimate building blocks of matter and energy.
Since physicists expect that a definitive model of quantization of gravity is waiting in the future, it is fuzzballs ( and other similar proposals in quantization of gravity) that have to be compared with gravastars, not classical black holes. And then experimental evidence has to be sought.