Orbital period vs mass distribution of known exoplanets:
https://exoplanetarchive.ipac.caltech.edu/exoplanetplots/
As you can see there, the type of exoplanet humanity has detected the most are Jupiter-sized exoplanets orbiting close to their stars.
For two reasons:
High masses aid the radial velocity method because they make their host stars wobble more compared to lower mass exoplanets. Lower mass wobbles are just outside the sensitivity range of our best spectrometers.
Also aiding in the transit method, they have a short "year" - typically just a few days, making them pass in front of their star more often. The likelihood of detecting these is therefore a lot higher during a given observation time. In addition, exoplanets that orbit more distantly from their star have a lower chance of having an aligned orbital plane, that makes them transit the star through our line of sight to it. The necessary angle of alignment is much tighter compared to closer orbiting exoplanets.
Earth-like exoplanets (~0.003 Jupiter masses, period= ~365 days) are currently outside the sensitivity range of most instruments. Jupiter-like exoplanets tend to reduce the brightness of their host star by at most a few % when they occlude it - Earth has about a tenth of the diameter of Jupiter, so less than 1/100th of its disk area, so when an exoplanet like it passes in front of a star, it only reduces its brightness by a one hundredth of these few percent.
This is where even 16-bit cameras cease to be useful because even if the exposure times are optimized to be as close as possible to filling their "photon count buckets" in a single exposure, Earth and exoplanets like it would only reduce the brightness by 6 instead of 655 (of 2^16=65536) counts, which isn't that statistically meaningful anymore with all the additional uncertainty that is involved when taking images.