CRT Gaming

I've done this recently with my 3080 with great results, although using an S-Video input instead of component. I first used this cable to adapt a displayport out to VGA, then used this adapter to go from VGA to S-Video (and it also outputs composite). I found it worked quite well, although the S-Video adapter needed some tinkering to get it just right (also even though the power cable is usb, a standard pc port doesn't give enough power, so you'll need a wall wart for it or else the colour will be intermittent). It's capable of downsampling from a wide variety of resolutions, so there's no need for a custom one as long as it's the right aspect ratio, though native 480 does sound neat.

Ive used: https://www.amazon.com/gp/product/B07FTN5NN7/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 to work with the steam deck and my laptop. Works pretty well.

I just wouldn't, to be honest. Connecting a modernen PC to an SD crt is a pain. A 2080 can't natively output 480i, so you'll either need an old Radeon card or a downscaler. Maybe look into the GBS-Control if you like tinkering.