It seems that you’re maybe rotating only part of the hierarchy that contains the character, but does not contain the glasses. You should go up to their shared parent / possibly even the root of the whole hierarchy, and rotate that entity.
Hmm now is this because of the use of setLocalEulerAngles function itself?
Because that would mean rotating the Player entity which is not what I want since that happens upon the player moving + rotating the camera.
Is there an alternative to the function, setRotation and setLocalRotation(-90, 180, 0) makes the character mesh disappears / leaves the viewport.
Like stated, everything is included in one .glb loaded from url. The glasses / accessories aren’t separate in terms of files. The character mesh loads this asset, the Player entity is it’s parent with scripts for movement, etc.
Using the tool, see if you can hunt down where the glasses are in the hierarchy. It does look like you rotating the correct entity, so if the glasses are a child of that entity, I’m not sure what is going on without a repro.
The issue is related to the animations and/or the renaming of bones.
As you are referencing by child index to do the renaming, this can be very error prone if something is moved/added/removed by the ReadyPlayerMe service:
var spine = hips.children;
var spine1 = spine.children;
var spine2 = spine1.children;
var neck = spine2.children;
var head = neck.children;
var headTopEnd = head.children;
var leftShoulder = spine2.children;
var leftArm = leftShoulder.children;
var leftForearm = leftArm.children;
var leftHand = leftForearm.children;
var leftHandThumb1 = leftHand.children;
var leftHandThumb2 = leftHandThumb1.children;
var leftHandThumb3 = leftHandThumb2.children;