You are in the best position to fix your sensors.conf file, all you need you get a basic grasp of the syntax, which shouldn’t be hard to figure out. At the end of the day, it’s a matter of disabling the sensors which don’t report useful information, turning on those which do, and changing the labels so you know what you’re looking at.
It’s something that’s usually only done once per machine, so there is no point in memorizing the sensors.conf syntax, even if it simple enough.
FWIW I remember the last time I used Xfce, their panel plugin did a decent work of figuring out stuff itself. You may still need to make some minor adjustment in the program’s GUI, but that holds true for Windows software as well.
Adding repositories should be mostly for software not included in the distribution itself, and distributions targeting end users try to cover all bases. If you’re using pure Debian things are a little more involved (because of their mission to provide an untainted FOSS distribution), but not by much.
Also I’m not sure what you mean by “just download” not working - you can indeed download software without using your distro’s package manager, and install it as well.
Usually this is not recommended to beginners because the package manager only knows about the things it has done itself, so basically software installed outside the package manager could mess with the PM’s job, and viceversa.
If you have a basic idea of what you’re doing, however, it’s not a problem, I’ve done so a million times with hardly an issue: it took me less than figuring out what was the Debian-approved (proper) way to go about building software, they have their own configuration stuff and customs, so sometimes I just find it easier to ./configure and make and then copy manually the files. Hardly elegant, but as long as stuff works without wasting too much time it’s fine for me.
As for drivers, one key difference should be pointed out: while in Windows drivers are, to simplify, mostly independent from the kernel, in Linux most drivers are ‘modules’, or part of the kernel itself.
Some devices only need a kernel module (and hopefully work out of the box, like say standard USB devices), some have a basic kernel module plus another piece of software (GPU) or binary firmware (network cards). For stuff like input devices, there is an X driver, that is not coupled to the kernel module (but needs it to work).
Indeed if you begin looking into the innards of an operating system, things get very complicated very fast, as both OS’s are extremely sophisticated and incredibly complicated piece of software - both try to get around the problem by making stuff as automated as possible, so that the intricacies are hidden from the user.
In a way, it’s like popping the hood on a car: as long as it works you don’t need to understand what’s making the car move, and it can be mentally packaged into a very simple abstraction.