One other thing to consider (not time-related) is that defocusing engraves on acrylic ends up with a smoother end result. You might like this post if you haven’t seen it before:
There are other techniques to speed up “engraves” but they almost all have tradeoffs in terms of appearance and are much more time consuming to set up. I wrote up a post on some experiments a long time ago:
It was an interesting experiment, but I never came back to it just due to the work involved in setting it up.