I've already edited it before posting to make sure it is not a duplicate and zealous admins are not reading
There is nothing wrong with our reading abilities.
but close it because it has the phrase dark mode in it...
Yes, isn't that you're asking? Support Dark mode, either by the site or by browsers / extensions.
What am I supposed to do to actually ask a relevant question that may have some similarity to an existing question but is certainly not a duplicate?
Explain with an edit what makes that your dark mode support request is much different from all we has before and why it is beneficial for SE to implement your suggestion instead of what was proposed earlier.
It is unfortunate that the post notices got so much improved that they now offer confusing advice. You are not supposed to re-ask the same question over and over again, despite that the post notice seems to instruct you so.
Note that if the answers found on a duplicate question apply to your question as well, they are still considered to be duplicate. In this specific case that seems to be "support dark mode" where the answer still is "Not yet".
Once substantially edited, the question goes into the re-open queue where fresh eyes re-evaluate the closure.
There is a chance users make mistakes here, that seems to be part of human nature.