This verse is cryptic at best, verging on unintelligible. So yeah, a word salad. Consider this: from an uninformed person looking in and asking for an explanation of what is meant by things like "spiritual warfare" and the word of God being a sword (which to someone who hasn't been raised around such concepts, can be quite confusing and rather alarming), quoting the Bible verbatim it isn't very helpful.
For - this indicates a follow-on or concluding statement is being made based on a whole bunch of other explanation that came before it, but without that context, there's confusion right off the bat.
our struggle - is this about a particular struggle happening at that time, like persecution of believers? Or is this more philosophical, like general struggles any time we start feeling like life is always an uphill climb and nothing's going our way?
flesh and blood - first thought is this refers to how the struggle doesn't involve physical fighting or face-to-face interactions, but then it occurred to me "flesh and blood" could be referring to family (our own flesh and blood) or a family of fellow believers. Knowing who this refers to would help resonate what is meant by the struggle against rulers (who after all, are also flesh and blood), etc.
against the rulers, against the authorities, against the powers - ...who were persecuting believers? or just in general? Either way, I guess the point is Christians should be prepared for and unsurprised by struggles imposed by rulers and authorities and the powers that be (so it is what it is, don't sweat it?)?
dark world - sounds ominous. Still trying to unpack, though, and the meaning is not self evident.
spiritual forces of evil in the heavenly realms - ah, here's the spiritual warfare part (maybe?). Well, it hasn't gotten to the fighting back part yet, just the existence of supernatural enemies. Presumably later in Ephesians it goes on to talk about how to combat these various causes of struggles, including but not limited to the heavenly spiritual forces (maybe by praying? or taking comfort by reading the word of God? or outright taking action using the Word as a weapon, like exorcism style commands or some other way to go on offense instead of defense?)?
I think a lot of people get frustrated when answers to their questions are "go read XXX X:X". For a believer, it is sacred text and it has the ultimate credibility, so they're going to infer as much wisdom out of it as possible, and lo and behold: the verse is crystal clear and unambiguous! But when read on its face by a curious person, even who earnestly wants to know more, it ought to be a fair critique to call passages like this a word salad.