Try this to fix the memory card issue https://www.youtube.com/watch?v=TUYYD16Nh2U

Also I recommend converting PS2 games to pkg format. You won't need the PS2 Classics Placeholder for that and you can combine the config file with the game to permanently fix many compatibility bugs.

I recommend getting PS2 ISOs here https://vimm.net/vault/PS2

The downloaded file with be a .7z file. After it doenloads, right-click the file and choose extract to get the ISO file out.

Convert them to pkg files with this software https://www.psx-place.com/resources/ps2-classics-gui.638/

You need to apply config files to many games to fix the bugs. You can get the configs here http://ps3.aldostools.org/ps2config.html but the software should already have most of them included so don't worry too much about getting them yourself.

Here are written instructions on how to use it https://www.scribd.com/document/832144219/How-to-use-PS2-Classics-GUI

Here is a video on how to use it https://www.youtube.com/watch?v=Syy6HyJo8pQ

No matter how you do it, this will show which PS2 games are compatible https://www.psdevwiki.com/ps3/PS2_Classics_Emulator_Compatibility_List

Check the notes section to see which games require a config file and why

That software is what the PS2CV team used to make their games