would it be possible to treat the chest node as if it were a mob entity instead of a node there is a mod called npcf
and if you use the trader mob and make it so that he only holds your items,he cant walk,use blend to make a chest model,and he has the chest opening animation i think you could make an animated chest
or instead of using npcf as a base code just start a fresh code of an entity that holds your items and lets you get them back
and looks and is animated like a chest
comment if you think thats possible and if it is i might try it