There is exactly zero evidence to show they cause the damage, the only evidence that once existed to say they caused the damage used 100% faked results, which didnt emerge until after the treatments based on it causing the damage failed to show any clinical benefit and stanford launched an investigation into the prof whose students produced the evidence.
They created several treatments that stopped them forming (most prominent being biogens). The result was no difference in cognitive function vs placebo and some 20% of the people who took it suffering from a heamoralgic stroke (which they covered up).
there's a reason that 18% of clinical trials around drugs against Alzheimer's still target plaques
also the etiological model evolved a lot (as others pointed out, it's removing blockage after the pipe has ruptured still can lead to a sinkhole forming later)
There are no sources, that is the definition of zero evidence.
Also, The fraud was found because the theory was invalidated, not the other way around. It was found that real life did not match the theory (by spending billions on human trials that all failed), so they looked back at the theory and found the results were fake.
When you say "the only evidence that once existed to say they caused the damage used 100% faked results", that is the kind of claim for which there could be evidence. What's more, it's the kind of claim that you should present evidence for when making the claim, since it's an attack on the credibility and honesty of those doing the study.
Just because amyloid/tau cause the damage, that doesn't mean removing them repairs.
If rust weakens a structural piece of steel, removing the rust does not repair the integrity of the steel.