— not answering your main question —
Using 2 links (just as a links) to that same article is bad for SEO.
Google and others will penalize you for Duplicated Content.
To do this correctly, one link shall be set as canonical.
The best is to do a 301 redirects but you can also use the Hugo aliases feature.
---
url:
aliases:
---
— back to your question —
Re to '/:year/:month/:day' just create a folder structure in YYYY/MM/DD and that’s will be sorted by default unless url specified. Then do alias manually or specify archetype for that do this automatically based on filename if you will be using hugo new to add post.
For example this:
title: "{{ replace .Name "-" " " | title }}"
Will create title automatically prefilled based on markdown filename (that may be your slug)
Next, just sort the year and date automatic generation.
for example:
aliases: /{{ dateFormat "2006" .Date }}/{{ dateFormat "01" .Date }}/{{ replace .Name "-" " " | title }}
The aliases however are meta redirects hence you will not be using them for positioning in search engines and the only 1 URL shall be.