Canon EOS M50 vs Panasonic LUMIX G7: which one should I buy? Which is overall the best for videos and stills?
Panny every time. Panasonic has a full ecosystem for the cameras and for shooting video, where the Canon is an also-ran. The only other brand worth comparing (unless you have the big bucks) is Sony. Canon shares the top spot in the still camera DSLR market, but they waited 10 years too long to get into the mirrorless market. Sony and Panny own that market.
No camera is really good at both stills and video. The two models you mention are designed specifically for shooting still images. Their video capabilities are provided for convenience Only. For proper video shooting, get a camcorder. I am partial to Panasonic for several reasons, if that does any good here.