Dangerous escalation, they know there would be more outrage and patriotism should the kremlin buildings be significantly damaged (they hit it once, but it was a small drone launched from within Russia)
The speculation is that the ones hitting apartments are suffering from EW.
They have several varieties (actuallly 100s), but the ones going into Russia are
- prop based (like the Shaheds Russia gets from Iran and sends at Ukraine, several varieties)
- cessna based (retro fits and now custom build frames too)
- small jet engine based (evolution on the Shahed style, Iran & Russia are working on this too)
They likely take off from several places within Ukraine. They have reached more than 1000km into Russia, so there is an amount of flexibility, depending on the model. They can take of from sufficiently far behind the active front and often take winding paths.
You can search "ukraine drone varieties" to get a sense
The quote from the Russian official about “attacking neighborhoods” is doublethink at its finest.