I just came across the Ruff Python Linter and formatter, which supposedly has "Drop-in parity with Flake8, isort, and Black" while also being 50x faster. It looks like it's being adopted by many important Python projects (pandas, FastAPI, etc.). It's probably worth trying.
Run flake8 over entire updated code-base and ensure compliance with PEP 8 – Style Guide for Python Code.