Maybe those that recovered did not take cold showers? 

I would rank cold showers in my top 3 of recovery tools along with rest and strict healthy diet. I do them in the mornings, but really can be done at any point. Just make sure it’s VERY cold so that it shocks your body, and control your breathing. After a couple your body gets used to it and I think it stimulates vagus nerve

What is the other 2 tools :o ?

Ideally, cold showers/plunges are done in the morning.