If you wanna go nuts on the data, probably Obsidian.md with the built-in Daily Note plugin and the Dataview plugin, which allows you to do all kinds of crazy operations on the data in your vault as if it was a database.
If you wanna go less nuts, obsidian still has tagging, linking notes, daily notes, and all kinds of other stuff built-in and is extensible by things like the Calendar plugin from the community.
And everything is stored as plain Markdown with the occasional hint of JSON (for some plugins) so you're not locked into using Obsidian until the end of time. Your data is yours.
(I realise this sounds like an ad but I've just been using Obsidian for years now and I enjoy it)