If it was this easy, the Russian would have tried that last May, or December, or even this May.
There is a very old saying, "you can't shoot what you can't see" and it's very obviously from day 1, Russia did not have a very good battlespace awareness. Which is odd given Russia should have enough equipment to do the task at hand, may not be as well as NATO, but certainly would have enough for Ukraine, you don't need NATO version of Battlespace awareness to fight in Ukraine.
The problem for these drone is, you need to know where your target is from, and the only way for you to do is to fly sorties over Ukraine and map out the threat. This is what and how we use EF-111 Raven during Desert Storm, otherwise they won't turn on their radar if you aren't attacking, which mean RuAF would need to shoulder majority of the work if they were gunning for Ukrainian SAM, which would mean attrition for Russian Air Force. and this is something I have a feeling Russia don't want to put their position in, again, it's quite evident that they don't even launch sorties to protect Russian Occupation Zone from Ballistic Missile or even drone threat, or even drone threat inside Russia.
And unless Russia start pushing their Air Asset inside Ukraine, they aren't going to be able to target SAM structure, and for the Ukrainian, their Anti-Air Defence would just get better as time went on with more Western Donation with more IRIS-T and NASAM or even Patriot promised by the West, so it's not going to be easier down the road for Russia.