setup.sh to see what the script did to install the software. It's not particularly daunting. After all, you are asking a question about a reverse engineering debugger!
The last thing the installer does is add this line (with $PWD expanded to the path of your git clone) to your
~/.gdbinit file .
If you remove that line, you will effectively disable pwndbg.
Then you are free to remove the
pwndbg directory (the git clone).
The setup script also installed (via pip) the Python packages listed in the
requirements.txt file. In general you can
pip uninstall the ones you don't want. But you need to be careful - using Pip to install packages can end up overriding the ones your distro package manager has installed, leading to incompatibilities.
Pwndbg should really use
virtualenv to set up a virtual environment just for itself, to avoid interfering with the dis to packages.