Hey @labris , Merci!
the team and I looked into implementing this with additive animations a while ago.
We keep a record of the animation definitions (start, end, loop…) and then “compile” to one animation group, using the additive flag.
works well in the engine, but the goal is to export it out to be used in Blender.
There, there is a weird bug, no one solved yet.
(Model disapears on additive animation group (GLB export))
As stated in that post, I would love to put time to help fix it