Quote

Astronomers have discovered a black hole lying just 1,000 light-years from Earth. The black hole is closer to our solar system than any other found to date and forms part of a triple system that can be seen with the naked eye.

https://www.sciencedaily.com/releases/2020/05/200506091537.htm

https://www.eso.org/public/archives/releases/sciencepapers/eso2007/eso2007a.pdf

Given the vastness of time and space, I wouldn't be surprised if there are BHs much closer than that.
This one was only detected because of the favorable arrangement of orbiting stars in that system.
Lone BHs, where the dust/gas from the supernova event has long since dissipated, or encouraged an existing nebula to Pop.I star formation ( in galactic arms, where we are ), would be almost impossible to detect