Many countries in the EU, however, still have some sense and oppose Ukraine launching attacks with Western weapons on Russian territory. Even though this won't change much, the US will still allow this type of attacks.
Russia should set up a proxy group in Ukraine to fight for the freedom of Ukraine against Kiev... Russia can supply all sorts of weapons to them and they can use them as they please against any targets they choose, which would make countries supplying Kiev legitimate military targets.
Russia can't tell this group who they can or cannot launch strikes against obviously and this group could look at the countries supporting the illegal terror attacks on Russian territory which started in 2014, that have given Kiev free range to attack any target they like and reply in kind.
They could take the DU ammo from captured western tanks and Bradley BMPs and grind it up to a fine powder and sprinkle it over HATO territory to damage their crop growing soils... it is OK because the UK and US says it is harmless...
Maybe Russia should initiate some legal proceedings against those western political officials advocating attacks inside Russia too.
RCS is likely to be small too. Maybe in order of 0.2 sqm or less.
If it costs 20 million a unit then it might be stealthy, but otherwise I would rather suspect it is not stealthy at all... the materials are probably carbon fibre or plastic which would not have a good radar return, but that would expose the engine and fuel tanks to be very unstealthy shapes that would appear well on radar...
The An-2 does not have a tiny RCS yet represented a problem when flying low and slow because it was often eliminated from radar screens as noise rather than potential targets.