Samsung Support is horrible. I was on chat for about two hours today about this issue. Their support knows nothing. What they do is look up your issue (I guess assuming that you are too stupid to do it yourself) and then they give you an article or the manual with the "relevant" page number but I found that they were grasping at straws and just picking out things at random, not even addressing my issue. I was then shuttled to a different "department" and then transferred again, lo and behold to the first person with whom I was dealing. They, of course, make an attempt to convince you that it's Apple's issue.
What model year is your TV? If it is 2017 or earlier, your TV would not be supported. I found this out on my own through research. My Frame TV is late 2017 and it seems that only 2018 and later models are supported. I'm pretty sure that Samsung could address this by way of a software upgrade but I guess they can't be bothered. Forget about their SmartThings app. You cannot use it to mirror from an iPhone. I'm totally disgusted with Samsung. Their support people have absolutely no product knowledge. So I have just hooked up an Apple TV for streaming/mirroring purposes. You can do a search for your TV to see if it is compatible but if the AirPlay setting in "General" is not on your TV set, assume that it is not supported.
My TV software is fully up-to-date. Airplay has not been added. so not sure where you got the information that one of the updates was supposed to address it. My screen looks exactly like yours with the Apple AirPlay Settings missing.
My gosh, I have a $50 Roku that streams/mirrors from my iPhone without issue. Samsung is a big fail here. I would never buy another of their TVs.
