Yep, a Whatsapp group looks just like regular SMS (text) chat, but with multiple people in it. You can send photos, videos, links, etc a lot easier than SMS. It also only uses data, so it makes for an interesting situation for telcoms (people don't care about unlimited talktime and SMS - they want data instead).
That being said, Whatsapp, despite being owned by Facebook, doesn't really connect with Facebook. You use your mobile number to sign up (unless they changed it recently), and it basically replaces your SMS/talktime/Facetime. Which means it looks nothing like Facebook groups or pages. It looks more like Facebook Messenger.
All that aside, I don't seem Whatsapp being used much outside of Asia.
And quite frankly, I mute practically all my non-goal-oriented Whatsapp groups because it easily dissolves into chaos. It has replaced the email spam that people used to send (chain messages, fake news, etc). You get aunts and uncles sending completely factually incorrect chain messages or you get spammed with gifs saying good morning.
The only decent Whatsapp groups I'm happy to part of are groups that are goal-oriented ones - planning events with friends, handling work projects, etc.
That being said, if you don't like Facebook groups, perhaps check into Telegram. Telegram often has more groups and handles it a bit better than Whatsapp. (And Telegram is more secure than Whatsapp.)
I'm still looking around to see if there are any Slack channels for parrots, but oh well.