Looks like very poor penetration on the welds from what I can see. Keep in mind those pictures aren't the greatest but poor penetration means a very weak weld.
The grade 5 hardware has got to go. Hitches get grade 8 minimum or nothing at all.
I might trust that setup to haul 500 lbs or so, but not much more.
You might get away with hauling more, but it's a total gamble over that....maybe even a gamble at 500 lbs from what I can see.
I'd say it's a good first attempt, but I would take it to a proper welding shop and let them burn those welds in good and deep with the right equipment and then pop in some proper hardware.
Nothing sucks more than seeing sparks in the mirror or watching your trailer pass you on the freeway.....