Deluge
Not sure(on my phone) but can understand it breaks when can neither read or generate new, so issue(core methods of daemon not available as not connected properly).
Btw for python -m venv, then --system-site-packages will enable sys.path on venv, and can also be toggled in the pyenv.cfg later, in venv dir. Need be enabled for the gtkui to work, as gtk bindings not available from pypi, and also if want use system libtorrent.
Also for pip, sometimes need -U switch for install, when already available(package to install). You need install libtorrent seperate with pip, and webui included with Deluge package.
I always make venvs when using pip so didn't knew about this change, sorry.