Your point on missing IR halos is valid, but don't overlook anomalies like Tabby's Star (KIC 8462852) [0]. Its odd dimming led to theories about alien megastructures like Dyson Spheres, though dust or comets are possible explanations. Still, Tabby's Star highlights the difficulty in excluding advanced alien activities with our current tech. [1]
This person [1] ran a data search for stars with a similar light profile (“slow dippers”) to Tabby/Boyajian’s Star, and claims to have found a cluster of similar stars in the region. But the results are not particularly high confidence and are probably just data artifacts.
[0] https://en.wikipedia.org/wiki/Tabby%27s_Star
[1] https://youtu.be/mZve2Oy3cFg?t=82