Poor timelapse quality with Logitech Brio 4K webcam

I'm trying to get high def timelapse video. I have a 4k webcam, and have made recommended changes to the Octopi code regarding image resolution. I am rendering at 60fps. The rendered video still appears to fairly poor quality.

What am I doing wrong?

After doing some additional research, I'm thinking the Raspberry Pi 3 that I have is not up to the task. Unfortunately, the Raspberry Pi 4 is sold out everywhere.

That shouldn't make it render and look bad, just maybe take longer. What are the settings you have configured for the timelapse? It could be an issue with bitrate or something.