I had this exact problem a whole ago, trying to find an alternative to OneNote. I went through many of the other suggestions in this thread but settled on Trilium.

Super easy to setup in a docker container. Self hosted so I control my data and access. Can by accessed via reverse proxy when I'm out and about.

Notes can be a mixture of text, pictures, code (with formatting based on language)

They are arranged in a directory structure with notes inside other notes under chosen topics down the left, and open notes are in tabs along the top, much like One Note.

The chrome extension allows me to quickly snip and send back screenshots or Urls of sites I'm on, and the android app let's me make quick notes which are filed away by date for later organisation (when I get round to it...)

The only thing it doesnt support, that I wish it did, is multiple users. I don't see why you couldn't just make another container for each user, just not very practical if you have a lot of users.

Interested to see how hot this take actually is but... The Nintendo switch is the best console ever made. As a lifelong Nintendo fan boy (Nes, right the way through) I may be a little biased but I have also owned various PS/Xbox and I don't think I've spent as much time on any console as the Switch. Being locked inside for a few years during the pandemic helped, but even a year or so after that I'm still playing. It helps that Breath of the wild is maybe one of the best games ever made, and Tears of the Kingdom is, so far, an incredible sequel. But also playing Overcooked with my wife and more recently Mario Kart (a personal "couples goal" of mine I never thought would happen) has filled so many lazy Sundays with hours of gaming joy.

Running up stairs on all fours, like a monkey I am 40 years old