

Remember Craigslist? I got a toploader for $40 with games because it had been stepped on and crushed! Some Bondo, paint, AV mod…
Toploader not recommended if you like to use Game Genie.
RGB mod: It’s expensive IIRC because you need to replace the PPU (video chip) entirely with one from an arcade board or a modern FPGA reproduction. Edit: Sweet Jesus, you’re looking at about $250 for RGB kit installation…
Game Genie had a thicker circuit board than a game cart, to get a good connection in the frontloaders. The toploader’s cart slot is pretty tight, to get a good connection. Combine these, and it feels like the cart slot is going to pull off of the circuit board before the Game Genie lets loose. Everdrive/Powerpak would work fine.
Galoob offered an adapter for the toploaders but they are extremely rare.
Honestly, even a Trinitron TV with composite looks as good as RGB at the resolution of NES.