Well on first pass, this looks unacceptable.
I have a 2017 15" model and a 2019 16" model. For both, I connected to a 3440x1440 60hz monitor through a Caldigit TS3Plus dock with a Display Port cable.
I turned on apple music, activity monitor, finder, messages, and loaded gmail and a google search onto safari. The older machine has many more applications running in the background and I have kept the new machine running over night a few times to catch up on indexing. After loading the apps I waited a couple minutes and then clicked them a little before capturing screen-shots. I watched both machines and attempted to grab representative screen-shots. I'm not using clamshell mode for either.
Here's the 15" (2.8ghz, 4 cores, radeon pro 555 2gb):
Here's the 16" (2.4ghz, 8 cores, radeon pro 5500m 8gb):
So with barely anything running, the new machine runs much hotter. The DC In is much higher. The fans are practically off in both scenarios. I usually override the fans to let them run much more often but I went back to system control for this test.
As well, I'm seeing the new machine spike to 200 degrees when loading more intensive applications and I have gotten the machine to where I can't cool it below 180 degrees with fans at full blast after running some more intensive applications. I can try to do a more intensive comparison later. Let me know if you have any tips that I can apply to make this comparison more equal.
Meanwhile has anyone tried the model with 2.6ghz, 6 core, 5300M 4gb?