You can AirPlay whatever you'd like from your iOS, iPadOS, or macOS device.

at least Sky in the UK explicitly block you from using airplay when the app is running. They detect airplay in use and overlay a gray box on the content. I’ve seen no work around for this and suspect it’s a sign of things to come for other broadcasters and media houses.

Which do not have porn apps either. But I can over complicate everything by streaming my safari session I guess?

I guess safari supports porn

You can Airplay any video content from the web, or mirror the screen.

So I use another device to browse and the TV only for watching. I get it, sounds annoying just to enjoy some porn

There’s always infuse player and plex, into which you could place whichever pornography your heart desires.

You can install VLC and enter arbitrary stream URLs to watch.

You can also use Plex to access a media server with whatever you want to put on it.

So no porn streaming at all?

Does VLC on Apple TV support all VLC codecs?

Sorry I don't know what you specifically mean by "porn streaming" are you talking about a dedicated app for a specific streaming service?

If so, I highly doubt Apple would allow those on their platform but I've never actually checked. There are semi-sketchy IPTV clients that you can use to watch what seems to be unofficial streaming services, so perhaps those can also be used to watch what you want?

As for VLC, it's open source I encourage you to do your own research as I can't answer your codecs question with confidence.

Well if I watch porn I don't download it and watch it later, but open some place app or website and browse videos on my TV to fap to comfortably from my couch.

To be fair my question is already answered, no porn support. You need a another device to stream from.