ADS-B out transmits your location and altitude to other aircraft so they get warnings if you become a collision threat. That’s good for everyone.
It’s expensive, at $2000, but then so is going down in flames while listening to screaming, soon-dead airplane occupants. As of Jan 1, 2020 every aircraft that flies near big cities or above 10,000 feet must have one. So if you fly above a few hundred feet anywhere near a city the likelihood of nearby traffic seeing you with their equipment is pretty high.
The device has its own GPS and barometric altitude source so all you must provide is money and power. It also reports on other aircraft if you have the appropriate phone app.
You don’t need to provide personal information. Just set it up to have a blank “N-Number” and have the category as UAV (unmanned aerial vehicle).
We’ve had collision avoidance on our aircraft (a helicopter and airplane) for some time and find it invaluable for knowing where traffic is. Just knowing there’s someone nearby piques our lookout and, in a few cases, it has enabled easy course changes to avoid collisions.
What the paramotor (or any ultralight) pilot would do is put it together the hobby battery (in a fireproof bag) in a pouch and wear it while flying. The battery must last for the flight’s duration but it’s pretty low consumption since the target audience is drone pilots. Search for uAvionix “Ping 202i”.