Being a Sony shooter, I urge you not to listen into hype. And the Sony is a hyped system. As with every tool, the Sony cams have their strong points as well as their weaknesses.
You could use your Canon glass on a Sigma MC-11 Adapter. But the results will vary. Some lenses work well, some don't.
If you really consider the step, I would propose to rent a Sony and the MC-11 and try the cam for a weekend. That might cost you 200 bucks, but it might save you a lot money - or help you to know why you are switching.
Speaking only for myself, I found that the Sony a7 III has helped me becoming a better portrait photographer, as the focus system really minimizes out of focus shots. The battery power is good and I never ran out of power in a shooting from a single battery. But I also dislike the mediocre EVF and the menu structure.
There is no perfect camera - there is only the best camera for YOU. And only YOU can find that for yourself.