Hey there!
"Remove as Not an Answer" is actually the answer to many of these points! This action is for any Answer that is either off topic, terrible advice, or a duplicate of an Answer already posted (as long as there is no new information). So this effectively closes an Answer. Coupled with downvotes, there should be no need for an "archived" answer action, I don't think
We're also planning to roll that action out to comments, so hold tight! For now, try to avoid marking comments as spam if they are not spam. You can ask a mod or admin to use the "delete" function available to them, or worst case, switch it to an Answer and then archive it (ugly, I know!). But we are working on that solution!