No smart phone... and no twitter app install.

Not so. I, too, have no smartphone and no Twitter app. Not ever been suspended (yet).

Stratechery interviews?

This is basically unanswerable by anyone except Twitter employees, since nobody else has any insight into their banning algorithm.

My understanding is that Twitter makes your delete the offending tweets.

So it seems like people should know at least what got them banned.

There’s a lot of abuse reporting abuse. If you interact with people, there are psychos who will put you in some sort of list and constantly report you.

I have a friend who is a minor public figure who gets taken down this way regularly.

I do wonder if people are tweeting out of character because twitter seems so good at provoking people.

The result is people get banned without objectively looking at the reasons.

That said I also know Twitter has quite odd rules about where it takes hardlines.

I started poking around his tweets, which led me to his reddit account, in which he complains about getting his Fidelity account suspended for what turned out to be posting his account number in public. I also found his blog, in which he has a post interacting with an obvious scammer and along the way gave out his social security number (it's still up there buddy, I'd think about blurring it out if I were you).

Anyway if that's a pattern it might have something to do with that.