No. That sounds like some bro science.
You can try it, but how will you know if it actually worked or not? Unless you have two plants use one as a control and the other one gets ice water. Then you’d have to send off some of that bud for testing to see if it was actually viable.
Quality genetics and care by the grower through the lifecycle determines THC output.
Lower room temps in the late phase of flower can increase THC to very very good levels. What you need to do is chop at the right time before THC degrades.
No, it does nothing. It's been tested by multiple growers and it don't do jack shit. It's what they call bro science. Like leaving the plant in 48hrs darkness before harvest, does nothing.