I don't believe that any Red Dwarf could be mistaken for a full Dyson Swarm. Some people more knowledgeable than me have put a lot of thought into the science o

I don't believe that any Red Dwarf could be mistaken for a full Dyson Swarm. Some people more knowledgeable than me have put a lot of thought into the science of this. You can probably find a more satisfying answer. As for the second part, that's easy. There are two key differences: 1. Young solar systems are around young stars and young stars are... young. We can typically age stars, particularly those close by; and 2. A protoplanetary disk is, well, a disk. A full Dyson Swarm is a sphere. To be clear, it's not a rigid sphere, it's just a collection of orbitals that end up occluding the star they orbit in the same way as small water droplets form a cloud or fog. Alsos I suspect that a protoplanetary disk, even if we're directly on its plane, won't be as dense as a Dyson Swarm.