We are there in October to get a cruise. We are vaccinated, but wonder if streets are safe since there was stuff going on last year??

\Istanbul is as safe as ever.
The pandemic regulations continue with a night & Sunday curfew and keeping regular restaurants and cafes closed (except for package delivery and pick up service). tourists are exempt from curfews but may need to eat at hotel restaurants. However all that should change by October with most of the population vaccinated by then.

The currently popular subject in the country is not terrorism but mafia/government collusion with a mafia boss, who broke off from government protection, releasing video tapes on youtube.

My wife swims at Iznik lake and joins zoom training while I suffer at home with stomach spasms and writer's bloc.