A lot of that could just be app farming. It's common to get moonshot app invites. That said I have seen people get "congrats on your 17x" emails while their score was being held for writing or fee waiver disputes, so it's not impossible.
I've taken the test 3 times - twice in South Korea and once in the US. I've never had any connection problems or any problems with ProctorU.
I've always used WiFi and my 2018 Macbook Air.
I am not a tutor but I have a list of contacts whom I got tutored from in South Korea. I can send you a list of their emails. Please leave your email and I will send the list to you.
App farming... normal. Helps your selectivity metric if you have a ton of apps relative to actual offers. Not to say you couldn't get in, but thats what those emails are.