I created a Drafts Action to crosslink a DTTG item and a Todoist Task.

It uses the first line of the draft as title for the DEVONthink item and the todoist task and the full content of the draft as content of the DT item. The title of the todoist task will be a clickable link to the DT item

The Drafts action can be downloaded here: https://actions.getdrafts.com/a/1lu