yeah, the behavior of these election systems is actually making me like First Past The Post more because it actually forces political change.

There appears to be no mechanism to reverse course before the demographic time bomb detonates and dooms western Europe forever

They're literally just here for money, stop giving them money and most of them will leave. The rest can be deported.

And because the imported hordes are overwhelmingly barbaric and violent, war will inevitably follow this replacement.

Also doubtful. Same as above, most will willingly leave.

Any real resistance will be from their parent countries not wanting them back.