Aidan Lawrence has released his “Mega MIDI” external hardware PCB board, which is a MIDI device using real Sega Genesis/Mega Drive audio chips. Having both a genuine Yamaha YM 2612 and a SN76489 PSG sound chip installed to this device. Users are able to link this device via USB or standard MIDI connector to your computer for MIDI playback, and/or to a keyboard/synthesizer for example to compose music that would sound authentic to what you heard outputting on the Genesis/Mega Drive. Aidan has put this up as on GitHub for free and is open sourced, but is selling these units being made by hand from his store front.
GitHub Project https://github.com/AidanHockey5/MegaMIDI
Write up from Aidan https://www.aidanlawrence.com/mega-midi-a-playable-version-of-my-hardware-sega-genesis-synth/