This reminds me of Kanboard in how focused and simple it is: https://kanboard.org
That's a really good thing, you don't always need heavyweight solutions with bunches of features that love to eat a lot of RAM (and CPU), sometimes a simpler option is fully sufficient.
Especially because this one doesn't try to tackle complex problems like auth, if it's for personal use, you can just put basicauth (over TLS), mTLS, OIDC (Relying Party) or whatever your heart desires in front of it.
That's a really good thing, you don't always need heavyweight solutions with bunches of features that love to eat a lot of RAM (and CPU), sometimes a simpler option is fully sufficient.
Especially because this one doesn't try to tackle complex problems like auth, if it's for personal use, you can just put basicauth (over TLS), mTLS, OIDC (Relying Party) or whatever your heart desires in front of it.