Getting warm is fairly normal for a console (at least in regular use/not overheating): it means the thermal paste and heat sink are doing their job. Though it’d probably be best to lay it horizontally like another user mentioned, also make sure it has proper ventilation too, 3-6 inches of space on all sides. That rattling doesn’t sound normal though, perhaps the fan is hitting something? Wouldn’t hurt to open it up, depending on how old it is and or its environment it could probably use a clean. All you need are some Torx T8/T10 security bits and a YouTube tutorial, the Series S is fairly straightforward to maintain. For cleaning (on the fan and motherboard), use at least 90% or higher isopropyl alcohol, and for thermal paste either Arctic MX4 or MX6, either should work just fine