If you set it up correctly, maintenance is low, and resource usage on the server is slim. Quite the apposite of Gitlab, for example.
However, after using SourceHut[1] for the last couple of months, I am convinced that their workflow is superior, and highly recommend using it. Using git send-mail is a joy compared to pull requests, and not having to enable JS for everything, even more so.
I am currently using their hosted version, but looking to self-host it for my company.