We took note of the drive’s temperature during some of our benchmarking runs.
The Kioxia Exceria Plus G3 doesn't appear to have any form of heatspreader installed but saying that the product label seems to be thicker than normal but there isn't any sign of anything like a copper layer being present. For safety's sake, you should use the drive with any form of cooling that your motherboard provides. We relied on the hefty built-in heatsink on our Gigabyte AORUS X670E Xtreme test rig motherboard.
The hottest the drive got was when it was being pushed very hard during the CrystalDiskMark 8 0 fill write test where it reached 39° C, comfortably under the stated maximum operating temperature of 85° C. For the non-4 K tests the drive averaged 35°C while for the 4K-based tests, the average was 30°C.