Is there a way to add "class" to my fenix5 plus?

It's in Connect (web), Devices and Sync Status, Fenix 5 Plus, Device Settings, Personal Information, Activity Class. I'm not sure if it is still necessary to enter this value, it may be calculated automatically.

I spent some time searching for it, I was used to Activity Class being one of the first things to set up on Suunto watches, but it is not part of the on-device setup of a Fenix. AFAIK Act. class was/is used by the FirstBeat algorithms (VO2Max, training effect, etc).

I'm sorry, I meant it class as an activity. On my vivoactive 3, I would select "class" on the activities because I literally take a class at the gym. Is there a way to add this to Fenix 5 plus?

Ha! That's indeed something else entirely. I'm not familiar with that activity type. Maybe you can copy the Cardio or Other activity and name it Class - if it is possible to duplicate the data screens and functionalities that the Class activity has.