This is the card I use for console capture and use a second one for my camera.

Plugged it in, opened OBS, added the source and it just works.

It really depends on how deep you want to get into it. The basic composite/S-Video capture devices on Amazon/eBay/AliExpress do work if you want something really cheap. Combine that with a distribution amp so you can play on a TV while you capture. Or if you want a higher-end setup, a RetroTINK-5X plus a component video cable and an HDMI capture device will get you the best possible quality from original hardware.

https://www.amazon.com/EVGA-Capture-Certified-Nintendo-141-U1-CB20-LR/dp/B09D8VYLY7/ref=mp_s_a_1_12?crid=25FQD4VNAXYFN&keywords=capture+card&qid=1677538746&sprefix=capture+card%2Caps%2C151&sr=8-12&ufe=app_do%3Aamzn1.fos.c1e7b9a2-53cf-44f5-ab39-5386af17669d

https://www.amazon.com/dp/B00F5R9TNM?ref=nb_sb_ss_w_as-reorder-mobile-t1_k0_1_13&amp=&crid=3TU721CL9PC8W&amp=&sprefix=hdmi+splitter

Set up I use. The splitter strips hdcp from hdmi for game capture/streaming.