The lunar module had a descent and an ascent stage, each was equipped with a single engine. During descent and landing, the ascent engine was covered and protected against flying regolith by the descent stage.
Velcro attached to the feet
Nonflammable Velcro pile is bonded to the decks'
top surface; a hooked Velcro on the soles of the
astronauts' boots provides a restraining force to
hold the astronaut to the deck during zero-g flight.
In practice, there simply wasn't a problem with flying regolith to begin with.
The Moon doesn't have an atmosphere. One implication of this -- and one that surprised a whole lot of people -- is that you don't get debris flying around when you fire a rocket engine. You get sheets of dust flowing radially away from the engine nozzle.
Of the Apollo missions, ...
"The sky is full of stars!"
While not on these three spacewalks, astronauts in cis-lunar have indeed seen stars, and this is documented in transcripts!
From Seeing stars from cislunar space?
Did any of the Apollo astronauts describe seeing the stars as they travelled between the Earth and the Moon?
Yes. They did see stars. Here is an ...
The lunar topographic camera ( LTC ) was used on Apollo 14 and 16.
Apollo 14 Mission Photography:
Hycon Lunar Topographic Camera.This electrically operated camera,
which was carried aboard the CM, was a modified KA-7A Aerial
Reconnaissance Camera, which, when used, was mounted in the crew
access hatch window. A remote control box and interconnecting cable