The Off Topic Topic

[grumbler]

How much can EM jamming fuck up controls of modern aircraft?

Against a modern manned, tethered, or completely autonomous aircraft, very little.  They are shielded from EM interference.

Against a non-tethered remotely piloted vehicle, the impact would depend on how "frequency agile" (able to shift frequencies when detecting jamming or spoofing) the link is, and how powerful and frequency-agile the jammer is. A jammer with a lot of power and a lot of frequency coverage would be a problem (but it trades power on a frequency for power across frequencies).