Why do my pedals sound like this?

I commute to work every day and I recently notice my pedals have increasingly gotten louder and louder. The audio in this video doesn’t do it any justice, I am turning heads with every push of the drive train.

I’m 98% sure it’s coming from the pedals, but it only happens when I apply significant weight to them.

One remedy I have tried is greasing the threads of the pedals, but that worked for 2 days.

*This is a single speed road bike