I had the same problem, the option doesnt appear, but I've found Facebook gives you another integrated tool where you can do it, it's called creator studio.
Facebook creator studio
There you can create a post from Facebook for Instagram, and checkmark that it also appears in certain Facebook page.
From the Instagram Help Centre page (same page link you have given in your question):
You can always report strange emails to firstname.lastname@example.org.
So, you don't have to click on the link in your email. You can forward this mail to Instagram directly.
Yes. So long as you are interested in the followers of Instagram accounts you know, this is possible. While a request to that URL will only return 100 followers, an automated repetition of that request along with some kind of scraping of the results modal will give you a full list of followers.
One way to accomplish this automation is by using PhantomBuster'...
They want Instagram to be mobile only. Instagram was always mobile only until recently they added some desktop functionality. It would make sense that they really want to differentiate Facebook from Instagram. They may do messaging on desktop in the future, but it's probably not likely.
From a marketing standpoint, impressions on mobile exceed impressions ...