As of 2023, there have been no matching circles found. But this doesn’t necessarily mean that the method has failed, simply that it was inconclusive. It could be that the last scattering surface is larger than the fundamental domain as stated is one of the cases. We may find circles in the future, and when that happens hopefully it will lead to great discoveries.
The reason behind the missing fluctuations still remains a mystery, but maybe one day it will be discovered whether or not the universe is indeed finite, or maybe they will be found.
The matching circles method is not the only method being used to discover the topology of the universe. Data from Planck agrees with data gathered from WMAP in suggesting that the universe is nearly Euclidean. The curvature of a Euclidean plane is exactly 0. Data calculated has yielded an estimated normalized density parameter 1.0009 ±.013. Comparing this number, to the possible size of the universe, it could just be a tiny microscopic dent in a flat sheet of paper. Trying to discover the shape of the universe while being an even smaller speck on the microscopic dent on a sheet of paper would be groundbreaking. It is amazing to think that we are gathering data from light years away, while we have only roughly traveled 240,000 miles away to the moon.