I did install Tahoma, set my DPI to 82 and removed antialiasing through the symlink on etc/fonts/conf.d; but the AA didn't change? It's as if something is having precedence over these configurations. Only when I disable it through the system settings it actually works.
That's probably because per-user configurations have precedence over the global configuration.
About recompiling to use Harmony; that is way out of my capabilities and I don't think its worth the effort since I have used other distros with it and wasn't satisfied with that either.
Are you sure that the other distribution you have used come with Harmony LCD rendering? Because many distributions (like Ubuntu, Debian, Void, openSUSE Leap, Tumbleweed etc.) enable this macro (Arch does not).
I believe that changing the LCD filter may be enough. Just need to find out how and why symlinking doesn't work.
The difference between the default and the light filter is not that big. You can find a synopsis here. Relevant for you is the second part with the autohinter.
If you still want to try the light filter, do the following. Create a file named
fonts.conf with the following content in
<!DOCTYPE fontconfig SYSTEM 'fonts.dtd'>
<edit name="antialias" mode="assign">
<edit name="autohint" mode="assign">
<edit name="hinting" mode="assign">
<edit name="hintstyle" mode="assign">
<edit name="lcdfilter" mode="assign">
<edit name="rgba" mode="assign">
<edit name="embeddedbitmap" mode="assign">
Adjust the settings to your liking and save the file. Logout to make sure the settings get applied after you login again (or reboot the system).
Additionally you can create a file named
.Xresources in your home directory with the following content to reproduce the above settings:
Adjust the settings to your liking (e.g. the DPI) and save the file. Paste the following command into a terminal:
xrdb -merge ~/.Xresources
No re-login required after this.