As for PS2 emulation, there are SO many devices which run it. These days the systems which are pushing the envelope on the retro handhelds are things like:

• PC gaming (Steam, GOG, Epic and so on) which is 100% super doable and impressive on Android.
• PS3 which is just really starting out, not fantastic but the games which do play, do so great.
• Switch! Super, super, super impressive on handhelds. Eden is the one emulator doing the hard work these days in my eyes. There’s also Ryubing (made by one of the original Ryujinx devs), but Eden is my pick.
• Wii U (a rather immature emulator, just getting started on Android).

It is a deep, deep world out there, with varying costs. But if you’re looking for PS2 games, upscaled and on the go in a tiny handheld? There is so many to choose from now!