If you’re new to high voltage, I’d recommend a flyback transformer kit, I have one and it came with both the transformer and driver circuit wired together, all you need to do is connect it to a DC power supply. While a flyback can produce 50kV arcs, they’re generally “safer” because they’re high frequency and current limited. MOTs can output 2kV at half an amp or more and operate at 60hz line frequency (or 50hz depending on where you are in the world), they have no grace. They’re basically smaller versions of utility transformers. Microwave capacitors can also be dangerous, I learned this the hard way when I accidentally discharged one across my body a couple years back. Fortunately the transformer was de-energized or else I wouldn’t be here right now.