How to Diagnose Disable-While-Typing Issues
linuxtouchpad.org
One of the more annoying things about typing with a large touchpad on a laptop, is that the palms or thumbs can occasionally brush past the touchpad and cause the mouse cursor to move. This disrupts your typing flow, and occasionally even worse–for example, clicking the submit button before you’re ready, or deleting text you just typed.

I have been facing the annoying issue of touchpad presses while typing since my last reinstallation. I had never faced a similar situation before (or I never noticed). The disable-while-typing gnome dconf was set to false. The issue was apparently with libinput not recognizing my touchpad as internal. Thankfully, that can be fixed with a quirk file. This askubuntu answer further clarified on how to write the quirk.

On the side note, I figured out how to disable the touchpad while I am using an external mouse.

gsettings set org.gnome.desktop.peripherals.touchpad send-events disabled-on-external-mouse

Although it sucks that this is not something I can just use the settings GUI for, I am glad I could figure it out before I lost my mind! ;)