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Joplin is a free, open source note taking and to-do application, which can handle a large number of notes organised into notebooks. The notes are searchable, tagged and modified either from the applications directly or from your own text editor.
A diary that keeps your private memories forever.
I switched to Journey for quite some time now. Mostly because it is way cheaper, and also has a windows application. In addition it allows to export all entries (docx & pdf) and it can import from Day One. The user experience is mediocre though, and there is no e2e encryption! https://journey.cloud.