It doesn’t sound like the traditional 43-folder storage approach for a tickler file is necessary here, and it is just the bringing content to the inbox on a specified date.
If so, there have been a few discussions on this topic over the years. I think the first one was this one.
Greg made some suggestions around using a defer tag and a sweep action. As an option, this would tie into the automated Shortcuts run described by @jsamlarose above. Something runs periodically to change the attributes on a draft so it shows it he desired location. This requires some additional meta data to be added to the draft as a tag, or even as say some data in the draft (you could use YAML for example if you were using Markdown( but this messes up the headings in the drafts listing because it is typically line 1) or externally held meta data.
Another approach is to use the existing meta data such as the creation date. This is something I covered in the above topic, and involves using an action (included in the post) to set the creation date for a future date and setting a workspace to filter out future dated drafts. This approach is overriding when you created the draft (which could be important information), but it does negate the need to have a periodic update of drafts.
There are pros and cons to both approaches as I think this sort of functionality is at a fringe in terms of capabilities.
Combining Drafts with another app like Things is not necessarily a bad approach. Things will give you a lot more power around time management and organisation than Drafts because they are occupying different domains and while there is some overlap, moving out of a domain is where you hit limitations. Jacob’s suggestion on automating your Things interactions with Drafts actions is very practical and just builds on your existing solution.