All in all, I would suggest the lens is the main problem. Did you use the kit lens that came with the camera? The kit lens combo isn't always that good and can indeed give results like this. I've had this experience myself, and as a result, can often recognise the result that it gives.
Also, in all the samples you provided, the 'look' of the photo is the same, which indicates to me the quality of the lens.
This may or may not be a factor, but do consider the lens. If it is a lens that came with the camera, take a look at 3rd party lenses from Tamron, Sigma, and Tokina, for example.
By @Ricky336
It's an EF-mount lens in the L series from Canon:
As mirrorless cameras are measuring the focus on the sensor, it is very improbable that there is a lens issue as there where with DSLR cameras and microadjustments. As not all lenses are equal, and this is the kit lens for a Canon EOS 5/6D, it's probably not the best lens they offer, but it is not of the cheap type, they use in the low end cameras. It still may be the issue, as the adapter ring takes it's toll, and the lens is not really build for mirror less cameras.
My guess is that the autofocus setting is to one shot, which is wrong for moving subjects. Even a short delay may bring the subject out of focus. A different assumption would be camera shake, but the stabilization on these cameras is amazingly good. But I have no experience with the adapter ring for EF lenses. It may be that the stabalization is handicaped against RF lenses.
Just for reference, I would refer @maria graziab50418227 to this video, which I found quite good for explaining the AF settings and tips on customization of the camera. As it is for wildlife photography, you need sometimes, however, to interpret the settings. https://youtu.be/CDZoXrBdyFo
... View more