I use CherryTree on my personal computer.
https://www.giuspen.com/cherrytree/
It’s really easy to use, is based around a tree based system of nodes, and allows for all kinds of formatting, and automatic syntax highlighting when you decide to throw a block of code into your notes. It’s also free.
For work, I am forced to use Microsoft OneNote, which is probably more feature filled than CherryTree is, but at the same time, I prefer CherryTree’s UI and node/tree method of organization.