Olympus E-M5 III has a
20.0MP Four Thirds (17.4 x 13 mm ) sized MOS sensor and features TruePic VIII processor. On the other hand, Panasonic G97 has a
20.3MP Four Thirds (17.3 x 13 mm ) sized CMOS sensor and features Venus Engine processor.
One other difference between these two cameras that is worth mentioning is that Panasonic G97's sensor doesn't have an anti-alias (Low-Pass) filter. Removing anti-alias filter increases the sharpness and level of detail but at the same time, it increases the chance of moiré occurring in certain scenes.
Below you can see the E-M5 Mark III and G97 sensor size comparison.
Sensor Size and Resolution Comparison image of Olympus E-M5 III and Panasonic G97 Cameras
Olympus E-M5 III and Panasonic G97 have almost the same sensor size, so neither of them has any significant advantage over the other in terms of providing control over depth of field when used with the same focal length and aperture.
Sensor size sets the circle of confusion, so it drives how much depth of field each
of these bodies gives you at a given aperture. You can calculate it exactly for the
Olympus E-M5 III
or the
Panasonic G97 ,
including hyperfocal distance.