Forgot to post this the other day.
On Thursday, I received all of the items I purchased from eBay and Digi-Key to make my very own multi A/V board for my Sega Genesis Model 1 to support Composite, audio (both Mono and Stereo via the headphone jacks), and RGB + Sync.
The items used were the following:
1) Blank PCB Board
2) Snipped off RCA jacks (from a VGA to RCA/s-video adapter that never worked and a component to 8-pin DIN for a specific video card that never worked), new headphone jacks for Stereo sound, and new 8-pin 262 Degrees DINs (lost 2 of them in the process because of the soldering iron heat), which are the same as the Commodore 64/128 systems.
3) 22 AWG color coated solid wiring (gray for Sync, Green for Chroma (Y), Blue for Blue (Pb), Red for Red (Pr) and right channel for the headphone jacks, Yellow for Composite, White for audio (both Mono and left channel for the headphone jacks), and Black or bare for ground)
4) 4x 220µF 6.3V Radial Electrolytic capacitors
5) 3x 75 Ohms resistors for the RGB lines
6) 1x 470 Ohms resistor for the Sync line
7) Loads of solder
Soon:
1) Plastic standoffs
2) Case with ventilation to prevent shortings
Here's the board in general:

Gallery: https://imgur.com/gallery/ANbTO5b
Stay tuned for a YouTube video for the comparison between Composite and RGB.
I used my DVDO Edge to upscale the RGBs and Composite to HDMI for my TV and set the aspect ratio to 4:3 so it doesn't look horrible when stretched.
Discord: https://discord.gg/U5dJw7x
Systems from the Compaq Portable 1 to FX-8350
Twitch: https://twitch.tv/retropcuser