Start with so-called beneficial nematodes sold for other purposes and applications.
You'll need a microscope with video capability to document.
You could still culture parasitic nematodes that afflict humans and prove.
You are not flying under any radar with your present tactics.
You already state they are not a medical device yet go to great lengths with your presence here about how they have helped so many afflicted with a variety of diseases.
Successful experiments on a wide assortment of nematodes would mean your zappers just happen to kill nematodes of a wide assortment, a gamut, from plant killers to bug killers to some incidentally on humans.
But not sold as a medical device.
Just like you are doing now.
Why don't you show your good intentions and start with live nematodes sold for other purposes?
It would be a start.
You wouldn't even have to culture them.
That has already been done for you.
It would be easy enough to do that.
It would not be terribly expensive.
It would be the start of an evidence of your veracity and good will to people who doubt your sincerity.
Ball in your court.
What will para do, people?
What do you think he will do?
What will you do, para?