its inpossible to have a armor stand wearing the elytra. right clicking the armor stand gives it as a weapon in the hand. and using replaceitem command does give it. but it doesnt appear on its back

steps:
1 place armor stand and turn on the arms
2 right click. and it will show in its hand
2.2 alternatively use replaceitem entity @e[r=3] slot.armor.chest elytra to force one on its back. still doesnt show up