Well. Genesis can be assembled..... As such....
You need to use a RaspberryPI or OrangePI, and load up RetroPI (OrangeRetroPI on the OrangePI).
Phil did a video on how to build your own cheap retro console.

In some countries you are allowed to download or make a backup if you have the original.
In some you are only allowed to make a backup of the original physical games media.
And then there are countries were every backup is illegal. Just check up on the law were you live.

As an example.... I am allowed to make one single backup for personal use or download a 1:1
copy, if I go out and buy the original version.
If the original version have drm or other copy protection, I am not allowed to crack it, unless
the protection prevents me from using it in other compatible machines.
I know that this is more a kind of music/video thing, that drm thing. Yet there are no seperate
law for videogames, nor seperate law for music/video. We only have one law for digital copying.

Sorry if this got a bit long... All I am really trying to say is to check the law were you live.
(yet again I got carried away, rambling nonsense) 😁