You don't have to go and change anything major, you can basically just write it into a script, and then make that script execute whenever Qubes boots. This is very powerful, as it puts you into the habits to do other cool things with this, the limitation is the sky, or your imagination.
Essentially, just open up a dom0 terminal, write "nano screen-settings.sh"
Copy paste, or write, your script in the window. When done, close it with shift+x, which gives you a yes, no, or cancel choice to save, pick Y for yes. Then it'll ask you the name, you already wrote that, so just press enter to confirm the name.
Now make the script executeable, do that with
sudo chmod +x /path/to/your/script.sh
Then you can open Sessions and Startup in System-Tools, or instead just write "xfce4-session-settings" in dom0 to open the GUI window. Go to the "Application Autostart" tab. Click "Add", write a name, whatever you like, and add the location of your script in the command-line.
This should essentially execute your script every time you boot up. You can also keybind it, similarly by going to System-Tools, Keyboard, and then the Shortcut tab. For example, it may be nice to have a keyboard to handle screen resolution, etc. for when you plugin a HDMI external monitor, projector, or similar, which annoyingly never memorizes last settings. So having a keybind here is very nice if you run into those situations.
This approach doesn't limit you to screen settings, you can do a whole lot of things with this method.
As for your wireless button, you can do the same as above, write it in a script, and keybind it. While the specific keybind key may not be changeable, you can literally pick any other default keys to keybind instead.
I'm not sure about the fan speed thingy, it sounds like you either need a better kernel module (kind of like an external, optional, secondary driver from the kernel's more primary drivers, if using windows language), or a poor setting in UEFI. It could also be a bad UEFI version that requires UEFI to be updated, but you may want to try other fixes before updating your UEFI, which can go wrong if not done properly, bricking your laptop's motherboard. But perhaps you have done it before, in which case, it's less dangerous if you know what you get yourself into here. But try see if you can find a kernel moduel first for your CPU/motherboard, try google any Linux systems using your hardware, this is not something unique to Qubes, but may likely appear on any number of Linux systems using this hardware.
I must have brainfarts today, I keep remembering things I should have mentioned.
In order to execute your scripts inside an AppVM, with keyboard controls located in dom0 or sys-usb, you'll need to use something like this, a command that executes a command inside your AppVM.
If the command in the AppVM is small enough, then you can also bypass the script in the AppVM entirely, and just execute the command directly from the keybind in dom0, instead of executing a full script.
You might have to modify it a bit, it can be a bit erm, how to put it, special at times. But once you have the right modified command down, you just need to back it up so you don't loose it again.
qvm-run AppVM "gnome-terminal -e command-to-execute -options, etc."
qvm-run AppVM "terminal" etc.
qvm-run AppVM bash etc.
Basically, it depends on the AppVM's terminal, bash and PID logic, and what not. Try experiment with it.