yes, my understanding is that the Apple Intelligence toggle that we have in iOS 26 is no longer available in iOS 27, at least in the betas thus far ...
You are correct sir. I just installed iOS 27 beta 7, and at Settings > Siri, at the very bottom, is a button labeled with red text saying "Turn Off Siri", but that's just for Siri. There's no longer a single option for turning off Apple Intelligence, which of course is the more overall, pervasive assistant. Instead, Apple has replaced it with a series of finer-grained options in the Settings app. In beta 7 (and one or two prior 27 betas?), weirdly (or stupidly) enough, several of them are at Settings > Screen Time > Content & Privacy Restrictions, where you'll see an entry labeled "Siri", and when you tap on that, the pane that's displayed is actually titled "Siri Restrictions", and this pane displays a section titled "Allowed Siri Version", under which are options labeled "Siri AI (Beta)", "Siri Classic", "Don't Allow Siri". Further down in the Siri Restrictions pane is an option labeled "Writing Assistance", whose choices are "Blocked" and "Allowed". There are other toggles and options related to other Apple Intelligence features here and there in the Settings app, but no longer a single toggle to turn them all off at once, so if someone doesn't want to see the Apple Assistant prompts across the board, they'll have to track down these options individually and set them to "Blocked" or whatever it's labeled as for each of these options.
In other words, while Apple has given users finer-grained options, it's also made the Siri and Apple Intelligence on/off settings much more confusing for the average user.