This one apparently works fine, though it looks like it's sold out at the moment.
That is a Carby.
Here is a Retrotink 5X https://www.retrotink.com/product-page/5x-pro
Here is a decent HDMI to component converter https://www.amazon.com/Portta-Converter-Component-Support-Extractor/dp/B00A8FIQXA/ref=mp_s_a_1_12?dchild=1&keywords=HDMI+to+component&qid=1626141120&sr=8-12
This isn't cheap but it's the best.
I thought I'd follow up to my post in hopes of helping out others. I finally got the GBS-C working as-intended with my PC and Switch. Here is what I used and how it is setup:
HDMI Source Device (Laptop/Switch in my case) > This HDMI to component converter box plugged into the YPbPr component inputs on the GBS-C. Other side of the GBS-C - VGA out port (using this cable) with the component ends plugged directly into my consumer Sony CRT TV. Inside the GBS-C software I enabled Component out over VGA and selected 15khz downscale, everything works perfectly including scaling and re-positioning of the image. The only thing to watch for is the GBS-C must be turned on AFTER the source input or it won't sync properly. I hope this helps someone out in the near future. :)
It's in stock at Amazon.
This or this if your console is a DOL-001 model. That will get you a "lossless" conversion to HDMI, which should help substantially. If you want near emulator-quality captures, you can combine one of the above adapters with an HDMI-to-component converter and a RetroTINK-5X or OSSC. For reference, here's a capture from my setup, which is GBI-HF 360p -> Carby -> generic HDMI-to-VGA converter -> OSSC -> USB3HDCAP.
That's a very long post so I may have missed something in it, but it sounds like you just need an Extron Crosspoint and some RCA-to-BNC adapters. There are S-Video-to-BNC adapters as well, though they're not quite as easy to find.
As for your GameCube, throw the Hyperkin garbage in the trash and get a Carby or Prism HD. If you need analog component output, a generic HDMI-to-component converter will work fine. This is assuming your console is a DOL-001, though. If it's a DOL-101, you're stuck with composite or S-Video/RGB depending on region.
