@triodug I tried plugging my Dreamcast into my elgato HD60s via HDMI converter and it didn't work, because its "480p" mode is 720x480 and not 640x480. Retro console video output is a whole new brand of autism, save the headache and money on looking for something HDMI and go composite.
The splitter: https://www.amazon.com/gp/product/B08L54X4JH
The usb capture: https://www.amazon.com/gp/product/B07NPFJJ7K/
The audio: https://www.amazon.com/gp/product/B00B2HP1MW/
I don't use the audio on the USB capture bc it's way way shitter quality from the capture box. Just setting up a mic input is way better and less latency (audio is more important than video)