After it started to charge more than I'm willing to pay, and limiting storage spaces, I stopped using it. And OneNote started to offer the same features and I had/still have license for it. OneNote is free now, I believe. I stopped using it as well -- I didn't like some of its features and how it works.
Since then I've been using just text editor and share the note via cloud services, gave up finding alternative solutions.
There is Joplin - https://joplinapp.org/
Open Source, free, available for all OS and mobile devices, and sync via cloud services. I like that I have the control how/where my notes are stored/sync'd.
Some notes on Ubuntu
If Joplin is installed through SNAP, due to SNAP's security model, it has some limitation where notes are stored/backed up for directory sync.
Notes are stored in /home/$USER/snap/joplin-james-carroll/13/.config/joplin-desktop
(See this by going to Tools > General) I don't think this location can be changed -- at least I haven't found how.
If sync to directory, due to SNAP model, this directory cannot be outside of user home directory. Sym link won't work.
If preferred, use Desktop installer version. There is no restriction which directory you want to sync (backup).
wget -O - https://raw.githubusercontent.com/laurent22/joplin/master/Joplin_install_and_update.sh | bash
Installer version stores the notes in, ~/.config/joplin-desktop
For terminal version of Joplin, https://joplinapp.org/terminal/
$ NPM_CONFIG_PREFIX=~/.joplin-bin npm install -g joplin
$ sudo ln -s ~/.joplin-bin/bin/joplin /usr/bin/joplin
Terminal version stores the notes in, ~/.config/joplin
Removing Installer version
$ rm ~/.joplin
$ rm ~/.local/share/applications/appimagekit-joplin.desktop
Remove note files and configuration
$ rm ~/.config/joplin-desktop
$ sudo rm /usr/bin/joplin
$ rm -rf ~/.joplin-bin
To remove note files,
$ rm ~/.config/joplin
Warning on Desktop Joplin on Ubuntu 20.04
This is for both SNAP and installer versions for Desktop Joplin.
Tools > Options > Application, there is "Show tray icon". This doesn't work for me. If checked, and close the Joplin window by click on "X" button, it disappears but stay in memory. Only way to get it back is run Joplin again. You have to File > Quit to properly quit the application. If "Show tray icon" is not checked off, closing Joplin window by clicking on "X" button will quit the application.