its mainly preference, the total damage at the end of the day will be the same with all of them.
lightning charm: very high maximum damage, very low minimum damage. huge difference between this points. 0-9 damage on level 1
wind charm: very high maximum damage, very low minimum damage. huge difference between this points. 1-8 damage on level 1
fire charm: higher maximum damage, lower minimum damage. big difference between this points. but more controllable damage, 2-7 damage on level 1
earth charm: high maximum damage, medium minimum damage. medium difference between this points. even more controllable damage, 3-6 damage on level 1
ice charm: medium maximum damage, high minimum damage. small difference between this points. very controllable damage, 4-5 damage on level 1
the most clear difference is between light and ice.
as ice charms have very controllable damage, you can plan fights better as you know about what your next attacks will do, there isnt much chance of variance.
if you see you will have no chance anyway, you can directly run and save the mana. but if you are inferior, there is no chance to win the fight somehow.
light charms can have a very high output when you deal top damage. this can allow you to beat e.g. well monsters you would not beat regularly or kill
normal monsters with 2 or 3 big strikes. this saves mana as well, but at the same time you can be very unlucky and just strike low damage for several hits.
its much harder to plan fights with this way, as you have to rely on the luck to strike big hits.
the other charms are rather in between as you can see from the top table, so you may choose a medium path instead of a very extrem point.
either way, you should try to focus on setups of a type, as this would help to increase your proficiency faster.
you can find a nice discussion about this over here: