Its a bit complicated, but there is a a way this can work.

Under Projectile.cs, add this line around line 27:

public bool stickToCharacter;

Under MoveEditorWindow.cs, add this before line 3652 (before the "Apply Gravity" line):

moveInfo.projectiles[i].stickToCharacter = EditorGUILayout.Toggle("Stick to Character", moveInfo.projectiles[i].stickToCharacter);

Now under ProjectileMoveScript.cs, add this around line 214 (before the comment line that says "// Get Auto Bounds"):

if (data.stickToCharacter)
{
    fpTransform.position = myControlsScript.HitBoxes.GetPosition(data.bodyPart);
}

This code will force the projectile to be constantly sticking to a specific body part. To make a projectile rotate around the character, make a game object rotate around the character, assign it a body part under Character Editor -> Hitbox Setup (collision type = no collider) and set it as the Body Part Origin under your projectile move file.
Warning: Manual rotation may not perfectly synchronize with the rollback netcode.