Newer microwaves don't use bulky HV transformers + voltage doublers for the magnetron anymore and instead use high frequency power supplies + step up transformers, and are noticably lighter

Yeah that plus they often contain beryllium oxide which is dangerous to inhale as a dust.

My understanding is that this risk is overstated. BeO dust can be dangerous, but new microwaves no longer use it as an insulator, and the amount of dust which is likely to be produced by breaking the insulator in older microwaves (rather than deliberately grinding it to a powder) is minimal.

I had the shameful experience of breaking one of this rings. I got so scared from hearing about BeO that I mailed a bunch of safety hazard chemists and doctors. Most of them told me BeO is not used anymore in most kitchen appliances MWO and that it's most probably AlO which is enough to dissipate consumer devices' power. BeO was used in high wattage or military devices. After digging magnetrons manufacturer data sheets I found mentions of AlO and Chromium but no BeO.

Could be. In my estimation - for the vast majority of even technical people it is probably best to dispose of a nonfunctional microwave rather than attempt a repair.

Caps shock can happen so easily. Lots of tutorials online on how to make a discharge rod.

I still have a dozen to make a 10kV ladder one day.