The Nan was like that when mine were young! She just had this 'thing' about mornings, sleeping past 7am EVER was unacceptably slovenly, and she was determined to always be the first to wish anybody a happy [whatever], so calling in at ungodly morning hours, often first light. She did that to everyone, adult or child, student or professional, day or night worker, 8 month old sleep refuser or not. Otherwise Nan was absolutely lovely (if a bit out there), but that shit was too much. Everyone just shrugged it off as one of her quirks.
Oh, and even if she was "wishing happy [whatever] first" I assure you her real motive was to make sure you were up. And some days, completely randomly out of absolutely nowhere, she would call or ring and come right out and SAY "well I just wanted to make sure you were up!" The cow!
Finally one very bloody early morning on my birthday, had JUST gotten sleep refuser down, was exhausted after a night shift, and couldn't have had 30 total minutes of sleep, and here comes that shout... followed immediately by the squall.
I was so absolutely furious, I told her off right there on the landing! I hissed and shouted (and I must have looked mental, haha) that she knew bloody well that I worked nights and had for ages, she knew that I was not just having a lazy lie in, and that she'd also very inconsiderately (hmm, actually, I don't think that was exactly the word I used there!) woken the baby who had only bloody JUST finally went down after a battle, and that she absolutely cannot keep doing this to me. There were more words in furious anger, and she had the nerve to look scandalised that I was unhappy!
BUT!!
She NEVER EVER AGAIN rang or called me early mornings, even after I got a job with day hours! AND I'd say within a year or two after I told her off, she actually stopped invading (shitting on) anybody's mornings! Genuinely, she did.
I suppose it's possible that she was simply, somehow, honestly oblivious to the fact it was a jarring, unwelcome, utterly unpleasant invasion. I am absolutely certain that I was the first/only person to ever have told her off for it. She may have done some thinking after that. Or she may have been afraid of getting shouted at by an insomniac madwoman in ripped old pyjamas, sunken eyes, and huge frizzy exhaustion hair again...
So, in short, try telling her off? And really letting it out, letting the half asleep and jarred version of you take over and do the talking. Perhaps she just doesn't realise how awful it is. It worked for me!
And, bonus, my entire family are all extremely considerate of sleep due to her traumatising us all for years and years, so nobody in even my extended relations would EVER dare ring anyone late or early unless it were a serious emergency.
Whatever happens, I wish you the best of luck (and the best of sleep) with it. I know how infuriating and invasive it can be. /hugs