See here: Laser engraving glass - tried several methods, here are the results - #31 by Hauke - 10W laser, 40% power, 400mm/min. No cracks. I’ve done several glass etchings this way, no cracks.
Hot water inside: I’d discourage that: Imagine the glass still cracks, breaks and water flows across rotary module and Y-rails… Not an optimal scenario IMHO…