This afternoon, I've been using my 10th gen 13" pro for about 3 hours, driving an external display and USB speakers through a Thunderbolt 3 dock. Not a tasking workload, just music, Excel, about 5 Safari tabs, and 2 MS Word documents. The temp has ranged from 40 to 55 and the fan has not come on at all. I've had the machine about 9 days and this experience is pretty typical.
I don't have the 8th gen base model to compare it with, but my model with 10th gen processor runs cool most of the time with little to no fan. I have to try to push it to get the temp up high and the fans to kick on.
I'm especially happy, because I had the opposite experience with the 2020 MBA I bought in March. It ran hot quite often, even for basic everyday tasks, and the fan was on quite a lot. I used a 3rd party app to disable Turbo Boost, which helped a bit, but I hate disabling a feature I paid extra money for. I returned it about 10 days later and ordered this new 13"MBP with 10-gen processor the day it was announced. Very happy with my decision.