I saw plenty designs for an air-assist nozzle.
None of them have the nozzle so low that it also shields the laser from your eyes.

I ASSUME this will be a lot safer for your eyes when you are working with it turned on in the room.
I still advise to use protective glasses when looking directly at it

Disclaimer: USE AT YOUR OWN RISK. Lasers are cool but can harm you.

I have the 2021 20W fixed focus Ortur Laser Master 2, which has a positioning block to set the correct focus. This nozzle is designed to replace that 30mm focus block; I designed it to be 28mm when inserted fully onto the laser.
Designed at a little over 12mm for a snug fit; you might need to sand a bit.

Air assist opening assumes a 6mm outer diameter tube.

Be sure to test if you have enough airflow before starting a cut.

Notes: 

I suggest printing upside down using NO support and placing a custom support block under the main nozzle.

See last photo (bottom view)
Else you will get support in the air-hose opening, which you cannot remove.