re3 and Miami were open-source decompilations of Grand Theft Auto III and Vice City respectively. They were released for PC in mid-2020, and then ported to Switch and Vita. The original project is currently on halt due a DMCA strike from Take-Two, owners of Rockstar Games, but a few days ago a developer called AJM ported them to 3DS.
3DS is not nearly as powerful as Vita, so dont expect the same level of performance. Pica200 GPU is really crappy and the I/O performance is probably one of the slowest ever seen in any handheld. Curren WIP is playable on GTA3 and not really there on GTAVC. Port also suffers from blending issues, stability problems and other minor glitches. Only N3DS is currently supported and there are no plans for o3DS.