When I started using three.js a few years ago, I did some testing with skeleton and bones. Maybe that would be helpful? (Some in German, but easily translatable into English.)
[solved] Problem porting SkinnedMesh from old Geometry to BufferGeometry
Skelett und Knochen V1
Skelett und Knochen V2
Skelett und Knochen V3
skeleton
Mara
https://codepen.io/hofk/pen/eWdZMb