We have walked on other celestial bodies, but we still burn toxic goop that destroys our atmosphere in order to buy chicken nuggets. Logic need not apply.
I accept your premise that parameters of technological advancement need not influence each other, but assuming that they correlate similarly as on Earth, prosthetics and interstellar travel might have moved forward by the same coefficient.
In that case, walking on the Moon is like using a rock for a prosthetic eye.
Actually if I remember correctly, younglings use weaker sabers that can't cut through as much as normal sabers do. Most early training is done with specifically training sabers like those.
Funny thing is that limb slicing is actually the primary goal of several lightsaber techniques, since the opponent will usually be trying to guard their vital organs and will leave the limbs relatively more exposed.
So pretty much what you would do with regular swords. Arms and to some extent legs are closer to you than the rest of the body so they are often the easiest targets.
There's very little Jedi in the Star Wars Universe so it's reasonable to consider the advancement of prosthetics in this universe indipendent from lightsabers.
We have been shown that there is some weight to a lightsaber when lit though. Like in Rebels and the Mandalorian/Book of Boba.
And this weight is different to how a normal sword would work. The length adjustment is to finetune this power/weight distribution to fit the user and their style of fighting. Which is why we get shotos and claymores, as well as different sizes for different sized species.