I bought a Retroid Flip and have been really happy with it. I grew up with the game boy and have owned pretty much every iteration. Authentic is good but I think the utility of the android-based handheld can’t be beat. Especially given the high cost of the originals.
I got a RG353VS off Amazon a few months back and am loving it. Good speakers, beautiful screen, USB C charging..... It came preloaded with a bunch of games.
How come it took 20 years for a popular console? Sure, it probably takes some effort, maybe X-raying the boards, but a schematic can be created by someone with a desoldering oven and multimeter. Or sandpaper and flatbed scanner. At least they're free.
Edit: apparently includes full board recreation, that's better
The information has been available for a long time. And the method to get it was done by sanding down each layer and making scans, and tracing each line.
Without looking to much into this, apperantly the main new thing here is the way this information is compiled. Which may be quite the improvement in accessibility
I'm pretty sure this has been available for a while. I was using this site when I was working on my senior project in GBA emulation a couple years back