@Mcast, that's a nice neat job you should be proud of.
If you want to mod it to be a switchable 3.3V/5V programmer, in addition to the Vcc pin lift already discussed, you need to add a tiny DPDT switch with one pole switching Vcc between 3.3V from the LM1117-3.3V, and 5V (via a polyfuse), and the other shorting V3 to Vcc in the 3.3V position to bypass the internal regulator. Where to mount it is the problem - if its small enough it may be possible to solder the switch body to the ground track along the board edge next to the three capacitors by the regulator, otherwise epoxying it on top of the CH341A chip would be a sensible option.
There's a good page about this programmer here:
https://www.onetransistor.eu/2017/08/ch341a-mini-programmer-schematic.htmlFinally, for those of you less experienced with SMD rework and board mods *PLEASE* for your and our sanity, and to reduce the risk of snapping the Vcc pin, get some 28 or 30 AWG Kynar wirewrap wire or magnet wire to do the mod with! If you *MUST* use stranded wire it needs to be something really thin and flexible, but with a good quality core,e.g. a single wire stripped from an old 80 wire UDMA PATA cable, ends carefully stripped, pre-tinned and trimmed to length *BEFORE* making the joints, and you need an order of magnitude more skill to get a decent result with stranded wire.