I'd suggest you look at the article at hardware info NL:
Test methodology is listed as
The installed Core i9 9900K processor was always overclocked to 5.0 GHz on all cores. We chose a relatively safe voltage of 1.3 volts, so that the overclock is sure to be stable. We perform two 20-minute runs in the Intel XTU stress test, recording the maximum temperature on both the front and back of the VRM components, measured with a Flir heat camera, just before the end of each run. Usually the second run is the warmest, but the difference between the two tests was never more than 3 degrees. The graphs always show the highest temperature measured.
Aorus Pro was 57°C on back and 59°C on front of the PCB , cooler than ROG Hero while using 15W less for margin of error difference in CB R15 (1402 for Aorus Pro vs 1399 for STRIX Z390-E)
Z390-E was 76°C on back and 74°C on the front of the PCB (119W load)
MSI Edge AC was 69°C on back and 66°C on the front of the PCB (122W load)
Taichi was 74°C on back and 73°C on the front of the PCB (127W load)
Z390-E should handle i9-9900k fine but wouldn't be my first pick.
Z390-H uses same setup as Z390-P :