the second option, dated links, would probably also show a directory of related articles if you visited the year/month directly.
i.e. /blog/2025/ would show you all articles from 2025, and /blog/2025/01 would show you everything from january of that year
the idea would be that the first option, immutable post IDs, would be customised by me at the date of posting, and never altered (or at least redirected to new location if necessary).
name collisions would probably be handled by a warning when i try to create the post, where i could probably just append a -202X or something to the end (if i'm posting two articles with the same name in one year, i have a different kind of problem altogether)