Something useful, submitted with good intentions, will be received well, regardless of when you submit it.
For example, my most popular ever submission (1341 upvotes) didn't get a single upvote when I submitted 4 months earlier under a slightly different headline.
"See this page fetch itself, byte by byte, over TLS" - repost
"Annotated Live TLS 1.3 Session" - original
The reposted title was way more interesting
I usually try not to repost, because I think it’s rightly frowned on, but I do have a few less extreme examples where the exact same post got to the front page a second time after sinking without trace the first. It seems kind of obvious that the timeline of the first few upvotes is critical, and somewhat random.