Currently, as of 6/6/24, the CreateHumanoidModel APIs (such as CreateHumanoidModelFromUserId) do not respect a game’s avatar settings (such as StarterPlayer.GameSettingsScaleRangeHeight and StarterPlayer.GameSettingsR15Collision). They instead spawn in at the player’s chosen scaling, and are given OuterBox collisions.
Because of this behavior, if you are spawning player avatars via custom spawn logic (not using Player:LoadCharacter()), you are unable to make use of features such as innerbox collisions. Scaling features have a workaround for this issue (HumanoidDescriptions allow avatar scale customization), but collision features do not.
Expected behavior
It is expected that creating a player avatar via avatar creation APIs would respect a game’s avatar scale & collision settings.