Please add the mwoauth module to the shared pywikibot installation on Toolforge in order to allow bots to log in using oauth without the need to install this pywikibot-related module to a local venv.
(Some background: I use a separate venv for each bot task in order to separate concerns, so I would have plenty of venvs to update if this request would be declined.)
Somewhat related requests have been made in T134600 and T143534, but the landscape has change a lot since then. There is some demand for oauth out-of-the-box for pywikibot, however.