The 33mm pad, this is for AM5 mainboard

I measured mine and it is exactly 33x33mm - did you possibly get the wrong size? It says on the packaging how big it is.

The size of the KryoSheet (0.20 mm) is 38 mm in length and 38 mm in width, which is suitable for CPUs such as the Ryzen 9 7900X3D, considering that the heat spreader (IHS) of these CPUs is approximately 37 x 37 mm. Therefore, the 38 x 38 mm KryoSheet is an appropriate choice.