GBA is a great platform for CS pedagogy too. There are a number university-level computational architecture classes that use it. And I think Nintendo could be amenable to licensing their IP for more curricula ;)
NDS development has always been something I wanted to explore. This article provides a nice excuse to get started.
Just to put things in perspective. DS could run a full 3D platformer like Super Mario 64 DS back in 2005 using only 32-bit ARM7 at 34 MHz. New PS5 specs: 8-core Zen 2 at 3.5GHz, 10 TFLOPs GPU, 16 GB GDDR6