@drylightn I just tested it myself and what I suggested is still correct. And you should be able to skip with any button on the controller, but that's isn't too important - that you can skip is.
Once you have configured every other controller but before you confirm the controls at the very bottom, use the D pad to move back up to the triggers. Then try to assign the trigger buttons, ensuring that they are set to +AXIS (Mine shows up as 2 and 5 for left and right triggers respectively).
@anakin1138 I haven't delved into the github for the core, but I believe lr-fbalpha2012 doesn't have Sample support currently, or at least from the time I messed with it. I even tried including the Samples in the ROM archive and it still didn't work.
By the way, video signal on cps2 arcade machine was indeed 16:9, but the rendering was on a 4:3 screen. Rendering cps2 games as 16:9 is a bug, it was fixed on lr-fbalpha in late 2015, and was backported to lr-fbalpha2012 a few months ago.
About using the old lr-fbalpha2012 because you got the wrong roms, why not update your roms instead ? If you buy the wrong tire for your car, do you buy a new car or do you go back to get the right tire ? I can understand using lr-fbalpha2012 on a raspberry in a few specific cases (i'm mostly thinking about svg and killbld here), but lr-fbalpha is overall better because a lot of bugfix and compatibilty was added in the last 5 years.