[jonbc]

Taskwarrior [0] has different dates you can set that allow some of the features you want. There’s a scheduled date (earliest date to work on task), wait date (hide task until date), due date (must be completed by date), until date (when to drop it since it’s too late to do now).

If none of those work you could create a user defined attribute for your desired feature [1].

0: https://taskwarrior.org/docs/using_dates/

1: https://taskwarrior.org/docs/udas

[Macha]

The biggest problem with taskwarrior is taskd and its use of client certs to authenticate which prevents people just using lets encrypt with it and having to manage self signed certs.