[schwartzworld]

Boiling water before freezing is another way of removing dissolved gases.

[brenns10]

Tested on this very website!

https://www.alcademics.com/2017/10/boiled-versus-rested-wate...

Conclusion they came to (your opinion may vary) is that it's not worth the time and energy to get e.g. 1/2" more clear ice.