The real answer to killer drones is a CIWS that can cover 2pi steradians and attack multiple drones at the same time, because otherwise it will be just swarmed by drones that quietly glide towards it, engines off, from several directions before entering the final dive.

Which means not everyone in this age bracket is prevented from leaving, only literal draft dodgers.

Because it's hugely politically unpopular. There's a risk that this will happen after the parliamentary election this autumn.

This is incorrect.

There's no need for a massive assembly plant to produce a lot of drones from dual-purpose components. Most of these components arrive across the EU border and go to random warehouses that have been converted into assembly shops. There the drones are put together, flashed with the latest firmware and sent to the armed forces, where they are armed and launched.

The bigger problem Russia faces is the surprisingly sorry state of its AA. It's been designed to detect and intercept strategic bombers and multirole fighters, but it's been almost 40 years since Mathias Rust, and it still can't handle a cheap and slow flying target, relying only on point defense systems that can be and are overwhelmed. Ukraine has inherited the same Soviet tech but managed to build a better detection system that collects and processes the data from thousands of cheap listening stations across the country.

What he didn't anticipate was how bad the roads in Russia would be and how long the Russian army would retreat along them. You can't resupply an army that is marching on a narrow dirt road through a forest because it's blocking its own supply lines.