We should be eating meat because we can cook it, and our ability to cook meat releases a lot of nutrients
This argument seems to contradict that our stomachs have a low pH to handle pathogens from uncooked meat. It would seem as though you would need to pick one or the other.
We can even ignore all the polyaromatic hydrocarbons and other carcinogens that are produced when meat is charred. It wouldn't actually matter if cooking meat were exclusively increasing the healthfulness of the meat. "Less unhealthy" doesn't mean "healthy". Technically, boiled sewage would be healthier than raw sewage, but that wouldn't be a great argument for the healthfulness in general. In order to make that claim, you would need specific evidence of the healthfulness of a meat-containing diet and you would need to show that you could only be healthy eating such a diet. Otherwise you aren't actually demonstrating that eating meat is necessary.
There's nothing stopping you from using this argument as an excuse to murder and eat humans, because human meat also has nutrients released when you cook it. To then only apply this argument to eating animals would require some justification.
This doesn't touch any of the ethical claims. The fact that you can extract ever so slightly more out of an unethical action doesn't mean that it suddenly becomes ethical. Giving a stolen car an oil change so that it runs longer isn't a great argument in favor of stealing a car.