That is too big for a transformerless supply to be economical. More importantly, it will need lots of circuitry to keep it safe. Additionally, if it uses the traditional circuit with a capacitor to limit the current, the power factor will be terrible, and the series capacitors will be physically large, maybe two of these:-
https://uk.rs-online.com/web/p/polypropylene-film-capacitors/1235097/
A little 5 W LED lamp can get away with a lot of things that a 500 W light can't. For instance, if a 10mm long, 8mm diameter capacitor is subjected to too much voltage because of a loose connection, and it explodes, the lamp casing will most likely contain the debris.
For a 500W light, you will need something like this:-
https://uk.rs-online.com/web/p/aluminium-capacitors/1443464/ and you don't want to risk them being mistreated.
You would be far better and safer to buy something like:-
It would need tweaking to make it a constant current device, instead of a constant voltage one, but that is comparatively easy, and doesn't involve high power electronics. The power supply also comes with a 12 V fan supply, which you'll need for the LEDs.