A lot of Wagtail usage is with Poetry. Tends to be projects with 30-50 dependencies. It "just works" but we see a lot of people struggle with common tasks ("how do I upgrade this package"), and complain about how slow it is. I don’t have big insights outside of Wagtail users but I don’t think it’s too different.
n=1 but i've tried "manual" .venv, conda/miniconda, pipenv, poetry, and finally now at uv. uv is great. poetry feels like it's focused on people who are publishing packages. uv is great to use for personal dev, spinning up/down lots of venv, speedy, and uvx/uv script is very convenient compared to having all my sandbox project in one poetry env.