WRT submarine Rostov-Been-Droned, it may take some time to learn how serious the damage actually is. The same submarine was hit almost a year ago by a cruise missile (IIRC) and was initially thought to be beyond repair. The Russians repaired it and were testing it to see if it was ready to be recommissioned. Rostov-on-Don might be scrap-worthy or it might have been near-missed but the crew submerged it to prevent further damage (like the US Asiatic Fleet did in late '41 and early '42 during bombing raids).