Ideas on what this is?

I took this video on May 3rd in Jeollabukdo, South Korea at 8:39pm. I had gone outside to set up my Seestar, and it was cloudy but I just wanted to acclimate it to the temp before the clouds disappeared based on the forecast. I suddenly saw this in the sky. It was a long oval, I guess you could say whale shaped. When it first caught my eye it wasn’t moving, but then within ten seconds of spotting it, it started moving at a pretty decent steady clip. It was not bright as it looked like it was either illuminated clouds, or something illuminating through the clouds. It was difficult to tell which it was. I started recording on my cell phone (Seestar would have taken too long to slew to it) and even panned down to try to give viewers a sense of the size (it was straight overhead so no poles or anything to align it with). It disappeared in the light polluted area of the sky (either was no longer visible or actually disappeared).

Seems everything has an explanation, but this one I just can’t figure out. The only thing I think it could be is maybe a spotlight for some kind of promotion, but those usually pan faster and I’m closer to the country side so not really sure what would be advertising. I know they can go pretty far. I am near a large park, but I can usually hear the noise when there’s a concert going on or something and it was quiet. I’ve sat on this for several days and am just getting around to post it hoping the folks here can provide answers. Thanks!