I'm a millennial and I don't do stuff on my phone either. I'm too focused on watching the zombies in front of me, staring at their phones, oblivious to oncoming traffic.
And yes I am a grammar snob, vain about spelling and punctuation. Way too vain to let a spell checker run. However, you can't always refine your message on the fly. Far as I'm concerned, all phone typing is first cousin to butt dialing.
I'm a 73 year old female, and I remember my English classes very well, proper punctuation, spelling, and having to diagram sentences. I had an English teacher who wrote in my senior yearbook: "To a girl who can write well." After all these years I still remember that...but don't ask me what I had for supper last night. 😂