(Serious):
Firstly, as stated, don't make two versions. Different colors if you want, white and black but design-wise, they should be absolutely the same. Since the system is as old as it is, it would be far easier to have it be a SoC with a couple of gigs of storage, as flash storage is stupidly cheap now.
Secondly, reuse the original molds for the system. No overhead, no paying to have it redesigned. Use whichever mold you want, but stick with the original. I myself hate mini consoles, and like with the NES Mini, I would have honestly preferred a 1:1 scale re-release of the NES, not something that looks like it belongs in a diorama.
Have it come with/use wired and wireless controllers simple Bluetooth, so you can use any controller you want and/or the ones it comes with. Again, using the original molds, so no additional cost there.
No Ethernet port is needed. Just have a cheap Wi-Fi chip, those are literally a dime a dozen and most PCB SoC boards have the slots anyway.
Regarding the games: again, flash storage is cheap. If you want to do physical releases, fine. If not, the card slot is unnecessary and can just be there for aesthetic purposes, like inserting a fake game card.
For the UI, take a page from the NES Mini, it was well designed. Also, include a service to download games for the system of course, not a free service, just buy the game, and that’s it. No monthly fees or subscriptions. The entire library probably only takes up 5-10 megabytes tops.
Use USB-C for power. A cheap knockoff smartwatch could probably run this thing, so it doesn’t need tons of power.
As for CD games, again emulation, no need for the CD addon aside from aesthetics, unless you want to do physical re-releases of the games
Lastly, allow ROMs to be loaded onto it from the start. You know people are going to mod/jailbreak the thing within a month, just let people do it.
Doing this without the extras, like the card reader, disc drive, and additional parts and electronics for this, a $50-70 price tag would far outweigh the production cost
