That’s exactly right. Cortisol levels do increase after hard lifting, and is a natural and beneficial increase. However, if the levels are too high it can be extremely detrimental (increased bodyfat storage and catabolism)
As far as the soreness issue, a good rule of them is 3 days. If you’re too sore to retrain the same muscle group after 3 days, either the volume is too high, or you’re not eating properly. There are 2 reasons for the 3 day benchmark.
First, your body will only adapt to a consistent stimulus. Meaning that the more often you can work a muscle group (providing adequate rovery time) the better.
Second, you don’t want to give your body a chance to “de-train”. I personally feel this is more of a psychological factor, but I notice if I’m out the gym for more than 3-4 days all of my lifts are down a bit from my previous workout, no matter how good I feel.
Short answer I suppose is this, a monster workout that leaves you hurting for a week won’t kill you once in awhile (and might be good if you know you cant make the gym for a few days longer than normal) but as a rule of thumb, it should be avoided.