One thing worth noting is our popular notion of what a star seems to be is quite different from what astronomers have.

One example, Canis Majoris has a radius of about 1420 solar radii. But its mass is roughly 17±8 times the mass of the Sun and therefore an average density of 5.33 to 8.38 mg/m3. “It is over 100.000 times less dense than Earth’s atmosphere at sea level.”

https://en.wikipedia.org/wiki/VY_Canis_Majoris

https://nineplanets.org/vy-canis-majoris/

Any decent human being would have called these Black Hole Suns.

Is there an experiment that could resolve this? Literally resolve these objects better, or otherwise distinguish between these hypotheses?

Is there anything behind these objects they could lens?

Dr. Becky take: https://www.youtube.com/watch?v=KuTVjuXu7uE

PBS Space Time: https://www.youtube.com/watch?v=FMdrD_jcYgE

love those channels

Soundgarden was apparently prophetic with their hit song "Black Hole Sun."