Separate work and personal tasks, see everything due

Only the members of that workspace. Every workspace is its own privacy boundary, enforced in the database itself. Whoever belongs to your family workspace sees nothing of your work workspaces, and the other way round. Your Inbox is yours alone and cannot be shared.

You can also restrict access tokens and calendar feeds to single workspaces.

No, neither for Jira nor for GitLab. tsk sync jira and tsk sync gitlab fetch issues on your own computer, with jira-cli’s stored login and your logged-in glab, and send only the list of issues to tasks. The corporate token goes only to your company’s Jira or GitLab server, never to ours, and our server never calls Jira or GitLab. So no admin has to approve a third-party app, and it works behind a VPN too.

For a timer, tsk login --scope sync creates a separate token that can do nothing but sync. tsk never sends descriptions, comments or attachments of external issues. If needed, a workspace shows only the issue keys instead of the titles; the titles then never leave your laptop.

Through a calendar feed. In the settings you create one or more feeds, each for the workspaces you choose, and subscribe to the address in Apple Calendar, Google Calendar or Outlook. The feed holds overdue tasks and everything due in the next 90 days, without descriptions.

With “Show task numbers only” the calendar shows just the number, such as #1234, instead of the title, for a calendar others can see. When you renew the address, the old one stops working at once. How often the calendar reloads the feed is up to the calendar app.