My working memory file is just a giant txt file that is synced using git to github. It's free and fast (because a text file editor like Sublime is fast and can handle a very large text file). You can also use it offline. The conflict is handled by git, which is familiar to a programmer.
It also feels more permanent. I used to use other note taking apps where the notes were thrown away after migrating to a new app because it wasn't that convenient to transfer between apps. Plain text can't go wrong in this matter.
I used Dropbox Paper and Google Docs before. Once you reach certain size, it is very very slow.
The caveat with the text file is the lack of fuzzy searching capability... but it's tolerable so far.
I used to have multiple files, but that didn't work well either. It's nicer to have everything in a single file where you can scroll through quickly. But as mentioned the fuzzy search isn't there though.
It also feels more permanent. I used to use other note taking apps where the notes were thrown away after migrating to a new app because it wasn't that convenient to transfer between apps. Plain text can't go wrong in this matter.
I used Dropbox Paper and Google Docs before. Once you reach certain size, it is very very slow.
The caveat with the text file is the lack of fuzzy searching capability... but it's tolerable so far.
PS. I've built my own git sync: https://github.com/tanin47/git-notes -- it is written in Go.