re: FPGA, the Analog Pocket with an Everdrive also works great. I use it to play GB/GBC/GBA games on my TV via its dock. Sadly, those don't support sleep and stuff but that's worth it.
Why bother with an Everdrive on an Analogue Pocket? Mine has only seen a cartridge once, just because my partner happened to have an old GB game she wanted to see if her save had survived on, otherwise it runs entirely off SD.
Not a bad reason, especially if you have saves on it. I'm sure there's a way to transfer them and make it work but I wouldn't be surprised if it wasn't perfectly straightforward so I can totally see not finding it worth the effort.
I never had a Game Boy, back in the day I was the kid tethered to the power cord with his Game Gear. I almost bought the adapter, but then I realized none of my games had saves so I had no reason to want to use the real carts.
I already had a GBA Everdrive but I picked a GB/C one up because for about a year after release, the FPGA cores didn't support the display emulation features of the Pocket, which is a good chunk of the reason I bought mine. I believe they are now all fully supported though. The Pocket's sleep doesn't really work with flash carts either, so arguably the core + SD card route is now the better option, though I still own my AGS-101 model SP and GB micro, and it's cool to play on those still sometimes.
