Theres multiple ps2 emulators on android, including AetherSX2, its NetherSX2 fork, Play! Emulator. Theres also other emulators I will not name that committed code theft for profits. You might want to get your facts straight before you act so certain
The Play! core in Retroarch doesn't need a bios but compatibility is very low as it's a work in progress. In all likelihood whatever you want to play won't be supported. If you want to use PCSX2 you'll be needing a bios. Where that bios comes from I leave to you. For what it's worth I didn't dump my own bios. It's a ballache so most people don't.
Kind of hit and miss. Best thing about this emulator is that it's like Dolphin where you can long press on an individual game and create specific profile settings. With games I tried, one game may work 100 percent speed with certain overclock settings while those same settings will slow another game to a crawl, just gotta experiment with yourWcPWN1f.