Mains electrical person here.
There is no reason to work on a 230V -> 5V converter.
They are common as dirt, and you can buy one literally more places than you can buy eggs. Every gas station, liquor store, smoke shop, five-and-dime aka dollar store, apothecary, grocery.
Their common-ness does NOT make them a good choice for hobbyist hacking. You found out why.
Hobbyists should never be opening up an AC mains power supply. The items are commodities. Simply obtain a UL-Listed AC mains supply that gives the low voltage output you want to work with, and don’t open it up or tamper with it.
If you want to work with high voltage but low current AC, such as a Jacob’s Ladder, then obtain a UL-listed, isolating, 24 volt AC power supply, preferably one with intrinsic current limiting, and an appropriate step-up transformer to kick it up to your high voltage. That makes it an isolated “service” which means if you touch one leg of it and building earthing, nothing happens. Even if you touch leg-leg, as long as your high voltage is limited to 5 milliamps (due to current limiting on the low voltage side), it is rather unlikely to harm you.
EVERY AC mains shock is death brushing against your shoulder
Every single time you experience an AC shock, it is because the conductances (1/resistance) of the various current paths just happened to be too little to kill you that day.
However, these ad-hoc current paths are highly variable. If they didn’t kill you today, they can’t count on doing the same tomorrow. The humidity in the air might change. Your skin might be sweaty.
A stun is as good as a kill, if you’re unlucky. The picture postcard example is electrical drownings. But you can also be killed falling off a ladder, or collapsing (face-planting) into the mains AC equipment you are working on.
Stay on your side of the wall wart
For hobbyists, there is so much rich and fertile ground to be worked in the low voltage DC space, that there really isn’t any reason to fool around in AC mains. And if you look at the countless electronic projects in kit form, or made in low volume (many things on Kickstarter for instance), it’s the same refrain: a complicated ingenious low voltage DC product, coupled with a commodity wall-wart that is UL-Listed. Even though the project/kit makes not attempt to UL-List.
(And BSI, TUV, ETL etc. are valid NRTL substitutes for UL; however CE is not, unless it’s built and sold at bricks-n-mortar retail inside the EU proper. Everywhere else, CE means Chinese Excrement, because there are no consequences for faking it).
Needless to say you void the UL listing when you open one up.
Some people deride that ubiquitous wall wart and wish every product had an AC line cord or socket on the device. OK, that makes the UL listing vastly more complicated. Now the device’s internal power supply must grind through the much tougher White Book rules applicable to AC mains. If you notice, the first Mac Mini shipped with a power block. That’s because Apple was able to push the power block through the lengthy and complex UL listing process without revealing to UL what the product was. The Mac Mini itself could breeze through quite late, since it was entirely low voltage. *So, do you want your kit manufacturer or Kickstarter small-volume builder to really have to grind through that expense and delay? No.