On the other hand there are plenty of datacenter located command/control systems that puppeteer vast fleets of residential proxies (and Russia is by no means the only one doing so), so it will be very telling to see what social media accounts go silent over the coming days and weeks.

> from one Yandex data center ASN

This is only one of two extant Yandex ASN, not an ASN specific to one geographic region/datacenter.

https://www.peeringdb.com/net/1751

The other one is this: https://www.peeringdb.com/net/20950

And the 200350 also shows a near complete drop off in bot activity:

https://radar.cloudflare.com/bots/as200350?dateRange=7d

> command/control systems

There is Hetzner for that.