Sounds like some super weird, extremely local issue. And yes, I’ve been using it as main mail account for (after checking) almost 9 years now, so that includes that period.
Not an entire year. It was 2-3 day outages, weekly, for quite a while. I've been trying to find the tweets, but as Elon took away tweet searching it's been a challenge to go that far back
edit I remember they were open about experiencing a denial of service attack over several weeks.
I would guess so? It was days. Many days of "No mail was lost but access is down" messages.