Yeah but try pressing more than 4 keys at once on the PS2 keyboard and get back to me

That is a limitation of the keyboard not the PS/2. Unlike USB which is limited to 10 simultaneous key presses, PS/2 supports full n-key rollover.

This, it’s why I still use the PS2 interface. Full n-key rollover is impossible for me to do without.

USB does not have that limitation.

Ah, had to dig into it. There was a long period of time during which you couldn’t find a USB NKRO keyboard. Seems that has been fixed.

What’s n-key rollover?