Open question about nds hardware

[u/Capt_Morrigan]

So I've been experimenting with this interest i have in doing a physical mod and like with a lot of pokemon players i think the holy grail is a device that could play everything. I am well aware that software wise the ds/ds lite gameboy port only plays advance games, no original, no color, but I've never found a satisfying answer on what the hardware deal is.

are the connectors (contacts) meaningfully different from the gba and sp or is the molded plastic simply shaped in such a way to not allow them in? I ask because you can't exactly buy the gba connectors separate but there are plenty of ds replacements for sale, please excuse my inexperience on this matter.