Do new aftermarket ignition switches work?

Yes. No. Sometimes. Maybe.
Some of them are good, but the truth is that a couple of years ago there was an offshore manufacturer that got the wiring wrong- you had to separate the wires from the plug and reinstall them in the correct positions. Keep your old plug and switch to reference them before you install the switch.
There may have been some other issues/other vendors, but that is the one that I personally am aware of.