@Jiryn
i am using the awesome lr-FBNEO Emulator, which is installed by default, for NEOGEO and most of the arcade-roms.
As a second option i use lr-MAME (current) for those few roms, that FBNEO does not support and i wish to have.

The DIP-Switches can be accessed by a Key-Combo that you can define in Retroarch/Core-Options.
AFAIR this option is called "diagnostic key" and the default input is "holding START-Button" (during gameplay/rom running).

Retroachievements are the cream on the cake imo!
Similar to Playstation-Trophys or XBOX-Achievements, just better (great widgets, leaderboards for all kind of stuff...)
Concerning Arcade-Achievements: only lr-FBNEO is supported, another point for this masterpiece.
As far as you want to play for achievements: keep your fingers away from the DIP-Switches as only default settings are supported (which is more than fair)
Fo further information just have a look here:

https://retroachievements.org/

Hyper NEOGEO 64 for Retropie?