DC-G9M2

Lumix doesn't have better photo IQ, they may have been talking about its Video quality which panasonic cameras are renowned for. If you're trying to keep things small I'd recommend going with the OM-1 or OM-5 vs the G9II. The G9 is considered large by MFT standards and is even bigger than your Z7. H

There are two options for "Not too heavy" and $2000: Canon R7 + RF 100-400: Low weight and good reach, but the lens isn't the brightest. Probably the best camera to fit your requirements. Sony A6700 + 70-350: Less reach than the Canon, but brighter. But unless you're in forests or other dim environm