Ideally it creates a CSV file and stores it on an SD card or something. I’ll even use on that requires an app as long as that app doesn’t make me create an account.

UPDATE:

I went with a Withings BP cuff. It doesn’t meet the above criteria at all, but I already had a Withings account from years ago before I was concerned about privacy so I wasn’t giving my info to someone who didn’t already have it.