As other mention already, those are normal temps for the Ryzen 9 3900X. In fact since youre onlyusing a 240mm AIO, I would dare to tell those are very good temps indeed, specially the load temps ~70°C.
Keep in mind that AMD and motherboard vendors are working on BIOS update and chipset drivers, so its not a bad option to try to keep your BIOS update to the lastest version available in your motherboard website. As for chipset drivers, always try to donwload them from AMD webpage (
https://www.amd.com/en/support)
As for things to do, you could check inside the advanced tab on the Ryzen Balanced Power Plan, and see if the "minimum processor cpu state" is set to 5%, this will make your cpu go to lower speed when idle (idle is when you leave your PC alone doing nothing, don't touch the mouse or watch a video in youtube, idle means doing nothing).
Now, one thing that sucks from the picture you posted is that your memory clock seems to be runing at only 2133MHz (1067 x 2), while your infinity fabric (fabric clock) is set at 1200MHz. RAM and Infinity Fabric should run at 1:1 ratio.
For example if your RAM is DDR4 3200MHz if should said: Memory clock: 1600, Fabric clock: 1600MHz
I think that you didn't turn ON your XMP memory speed profile in BIOS (if you build this PC). What memory did you bought?, or was this a prebuild PC?
Anyways in order to tell you more, we need more details like Motherboard brand and model, RAM brand and model, etc.
Cheers