For the last half a year the number of indexed pages for our site went ~100M pages down, and it's been on this lower level for quite some time already. The number of visits, sessions and crawled pages didn't really change since then. After deleting some old parts of robots.txt, the number of blocked pages dropped by 90% and is really low currently. Indexed pages number didn't increase though.
How reliable the Index Status in Google Search Console is? Should this drop alarm us if no other metrics are affected in the same way?