system
Given the following post, respond as if you're commenting on Reddit:
human
[WH40k] Are there any really advanced human worlds that have been recently discovered by the Imperium?

I know that warp storms can have strong spatio-temporal effects that can separate a world or system from outside access, so has the contemporary Imperium encountered human colonies that still retain the high level of technological advancement present during the pre-Age of Strife era?

For instance, the Luna Wolves encounter the human Interex during the Great Crusade whose mortal weapons and warriors are a match for the Space Marines when fighting breaks out, could it be possible that a world containing advanced human civilization or even a functional STC be lurking about somewhere?
gpt
In the Chaos Daemons codex (I think it was that one) it was mentioned that there was a planet who had completely conquered disease, which requires a high technology level and lots of research.

Then, of course, Nurgle took issue with that and wiped them out in under a year.

There are really advanced planets in the Imperium. They are generally paradise worlds. There are also planets who were isolated and progressed independently, leading to a non-religious view of technology, which would result in a faster level of technical advancement.

The Adeptus Mechanicus would be inclined to stamp the last one out, however.