Miyoo Mini plus and Ambernic RG35xx are probably what you want. I have these two devices and the 353V, all three are quite nice but the MM+ and RG35xx are better to your needs and are probably better for beginners.

Personally I would go for the MM+. Definitely install OnionOS if you get a MM+ or GarlicOS if you go for thr 35xx. (JELOS is my pick for the 353V) These custom firmwares are far more polished and have more performance than the default OS and have tons of great features and community applications.

I find playing Nintendo games is always best on Nintendo systems. I use a hacked 3ds for all my handheld games including Gameboy, a hacked Wii U for Gamecube, Wii, and Wii U games, and a hacked Switch for everything else.