Brisqi is an offline-first personal Kanban app with cloud syncing and end-to-end encryption. With straightforward, clean, and practical UI, it gets out of your way and lets you focus on the tasks.
It is free to use the offline desktop app, no signup or internet required like other web apps out there to start using it.
The main advantage of using kanban offline would be to have access to unlimited attachments. Well, this program does not support attachments......