I can’t see any suggestion that accounts already 12 months since they were deactivated won’t be nuked in July. You’re potentially getting a months notice in the short term.

Looking into the actual announcements, they're not 100% clear but I'd be shocked if they skipped the archival period for old accounts. But also they originally announced this a long time ago and the official page says they've been rolling it out since January last year.

I wouldn’t want to gamble on that assumption.

True, but if I was worried about having too many accounts to track down in the next week I would go ask them and also I would have probably started doing something in the last year plus.