"They are well equipped", he said. And yet, their magnetic and plasma weapons are weaker than xcom conventional gear...

I propose to add all Advent soldiers an analog of the Channeling Fielding ability. The difference in ability is that there is no infinite increase in damage (3 maximum). This ability will immediately explain the effectiveness of armor and weapons and will not make significant changes in the balance (damage will increase to 4-6, which will not have a serious effect). I ask to forgive my bad English.

It would be nice to add this effect for any damage taken (including grenades or flamethrowers).
If you can - make it a separate perk (addon) with the choice of who should give it.