> replacing a real radio beacon with its true position via GPS / IRS
That's the last thing you want to do. Here in Europe, we're dealing with serious issues because the Russians are jamming GPS from somewhere in Kaliningrad, but unfortunately we can't respond adequately without legitimately risking WW3.
Depends on what you mean adequately. We probably shouldn't carpet bomb them. But there's a lot more that could be done - turning the weapons donations to Ukraine from a drip-drip of the spigot to a firehose should wrap the war up.