I'm running 1909, and took the KB4565483 update yesterday. Needless to say, I am now doing a full re-install of 1909 April, and WILL NOT take the July update! Taking this update hosed my gaming performance, causing massive micro stuttering to an unbearable point. The re-install is due to the fact that my backup image was corrupt.
The micro stutter was bad in GTA 5, which made driving a vehicle almost impossible. In Ghost Recon Wildlands, it would show itself as a full on (intermittent) freeze stutter, which occurred at equal intervals (did not take exact time measurements).
Not sure what the update changed, but I unfortunately couldn't roll it back. And it was bad enough to cause me to painfully re-install everything. I'm running an ASUS Maximus X MoBo, with 32GB Ram, i7 8700K CPU and dual Nvidia GTX-1080's in SLI (pulling 3 4k monitors). I had absolutely NO issues with performance before the update, and can verify that it was this update that caused the issues (because I stopped GTA 5 to take the update, then went directly back in after restart).
This is why people turn off automatic updates! As a developer, I can say, with absolute certainty, there is no way Microsoft can test for every scenario and hardware configuration. Just a heads up to anyone who has the same issue. And from now on, I will image my system partition before I take any more OS updates from Microsoft.