To offer you gear advice it would be helpful to know some details about your situation:
1. What is your budget - by which I mean a number value. We need to make suggestions that you can afford.
2. What subjects do you want to take photos of? That helps us decide what lenses you might want to use.
3. What do you want to produce? i.e. social media, digital display, small-medium prints or very large, detailed ones. That has a major impact on the investment you need to make.
4. What are you prepared to carry? Do you need small and compact, or something larger?
5. Do you have any further constraints: e.g. eyesight, injuries, need to travel so want very small/light etc.
Based on what you have indicated so far, I would not recommend either the M6 versions you mention. As Rick wisely said the M-series are living on borrowed time, but further to that, the M6 bodies do not have a built-in Electronic Viewfinder and although you can add an external one, at some expense, it is not an effective solution. Why do you need an EVF? It's about stability.
If you want to shoots sports, you need a long telephoto lens unless you can guarantee you are really close to the participants - such as table tennis. When using a telephoto lens, how you hold the camera is critical and that become more so the longer the lens. Holding it like a cellphone, which is how one normally would use the M6, is not a stable platform. You need three points of contact to your body (like a tripod) to steady the camera, as per the enclosed images. To make that possible you need to be able to bring the camera to your eye, and that demands a viewfinder. The M6 was designed for social work, street etc., where one is likely to use wide-angle (short focal length ) lenses. There are much, much better cameras out there for wildlife work.
