We've officially found 6k exoplanets, NASA says
space.com
space.com
Using our current technology to look at our solar system, we probably wouldn't see a habitable planet either.
Looking at https://science.nasa.gov/exoplanets/discoveries-dashboard/ , a planet with one earth mass and a 300 day year is simply outside of our ability to detect. Not to say that those are requirements for habitability; but they are requirements to detect the one habitable planet we know about.
https://www.stellarcatalog.com/stars.php?offset=100
Actually getting a spacecraft to them in a reasonable amount of time is still well beyond us. But if we could get a probe up to relativistic speads, that would put missions to nearby stars on a similar timescale to existing space missions.
Our ability to actually get