Fan issues have far more to do with what software you’re running than anything else. Most people are unaware that many applications these days are either “Electron” “apps” which are basically web browsers behind a thin layer of JS that pretends to be a native app, or they run on a core of Java. Both of these are horrifically inefficient uses of system resources. Chrome (the browser) is another horrible abuser of both RAM and CPU and is notorious for stealing tons of compute resources it doesn’t appear to need. My point is, unless you know that the software you’re running is highly efficient, your computer could appear to be doing “nothing” from your perspective and in fact be working it’s metaphorical ass off behind the scenes to run inefficient software. Depending on how much of this sort of software you run, how many system extensions you’ve installed or background apps, etc., your base compute load may in reality be far higher than you think it is or “should be”. Having a faster computer can, in some cases, even be “worse” than a slower one as it may trigger some software to engage more advanced (or sometimes just plain more wasteful) algorithms than if it detects that your system is slower or older, outweighing the advantages in your newer hardware (which are more marginal than the industry would like you to believe, also).
I run several macs with a wide variety of software. When I’m running the Java-based Eclipse IDE or Matlab software, my system fans will sometimes spin up doing the most basic of tasks or even nothing at all (from a user perspective). When I’m running the JS-based Atom editor, same thing. When I run optimized software like BBEdit, Ableton with extremely efficient plugins (Valhalla, Softube, etc) I can push the system remarkably hard before the fans even think about firing up.
So, in summary, there are so many factors that affect your system thermal load and most of them come down to what you’re really asking the computer to do and how efficient that code is, along with how many bits of code you’re really asking it to run at the same time, counting hidden, background tasks, system extensions/drivers which may be poorly written, etc.
The thermal performance of even my widely criticized 15" 2019 MBP is still fantastic with the right software on it, and while it can certainly be improved (the 16" shows a marked improvement, for instance) there will always in every brand of system be some thermal limit compromise somewhere in order to gain battery life/limit power consumption, increase performance, reduce size/thickness/weight/complexity/cost, etc. Treat it like any other ordinary limitation you’d run into (compute, memory, storage) and iteratively identify the causes in your specific situation. You’d be surprised how poorly some very popular software behaves on some systems!