Instagram currently has a closed posting API that they rolled out with a few partners during this beta test phase in 2020. Hekadoc is on standby and as soon as granted access to that API we will allow posting.
That’s why, unlike other channels, Instagram is currently semi-automated on hekadoc, with an email reminder on the scheduled date and time. Content and media will be attached to that email.
Facebook hasn't announced a shared date and time of when the beta phase will conclude and the API will be available to other partners.