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, can be copied, tagged and modified either from the applications directly or from your own text editor. The notes are in Markdown format.
Notes exported from Evernote via .enex files can be imported into Joplin, including the formatted content (which is converted to Markdown), resources (images, attachments, etc.) and complete metadata (geolocation, updated time, created time, etc.). Plain Markdown files can also be imported.
The notes can be synchronised with various cloud services including Nextcloud, Dropbox, OneDrive or the file system (for example with a network directory). When synchronising the notes, notebooks, tags and other metadata are saved to plain text files which can be easily inspected, backed up and moved around.
Screenshots Joplin for Linux