Lol, I ran into the same issues myself
From
https://github.com/Matoking/protontricks:
To use Protontricks as a command-line application, add shell aliases by running the following commands:
echo "alias protontricks='flatpak run com.github.Matoking.protontricks'" >> ~/.bashrc
echo "alias protontricks-launch='flatpak run --command=protontricks-launch com.github.Matoking.protontricks'" >> ~/.bashrc
You will need to restart your terminal emulator for the aliases to take effect.
Edit: I should add that I installed via the flatpak
so might have just been this line
echo "alias protontricks='flatpak run com.github.Matoking.protontricks'" >> ~/.bashrc
from
https://github.com/flathub/com.github.Matoking.protontricks