Diagnosis
It's normal for it to be warm, but not "super hot." Excessive heat usually means it's working too hard on a poor Wi-Fi connection or stuck in a background process.
How to Fix It
First, check its Wi-Fi signal. In the Home app, its status should show a strong connection. Move it closer to your router or a mesh node. Weak signal forces the internal processor and radios to work harder, generating more heat.
If That Didn't Work
Unplug it for 30 minutes to let it cool completely, then plug it into a different outlet on a different circuit if possible. This rules out a power issue. If it immediately gets hot again on a strong Wi-Fi network, contact Apple Support.
Heads Up
Do not place it in an enclosed space like a cabinet or on top of other heat-generating electronics. It needs open air around the entire body for its passive cooling system to work.