Is it possible to have almost all old games on my system?

Hello, everyone.

My system is a modded new 3DS XL, with a 128 gig sd card when I bought it from eBay.

My mind is kinda like that of someone who wants to have everything, so I managed to get (of my interest) almost all 3DS and DS games alongside some VC injections for NES-GB.

I have about 1.3 gigs left and now I’m a bit nervous about running out of space. So, I have multiple questions:

1. Is it better to play NES and SNES games on the modded Wii U and add them there or keep them on the 3DS? Any good emulators for just NES, GB and GBC besides VC? I could find snes9x for SNES, so I guess that's useful?

2. any good way to run GBA games? Because I don’t want to run out of menu icon space and it looks like openagbfirm is the best way, but turning the system off to get to it feels like such a hassle.

Sorry for the rambling, I just want my system to feel like the ultimate Nintendo machine as much as possible.

Thank you