DOSBox Pure, created by Psyraven in 2020, was designed specifically for RetroArch/Libretro.
Features
Single-playerMulti-playerFull controller supportSteam CloudCo-opOnline Co-opPvPOnline PvPDownloadable ContentRemote Play on PhoneRemote Play on TabletRemote Play TogetherRemote Play on TVShared/Split Screen PvPShared/Split ScreenShared/Split Screen Co-opLAN PvPLAN Co-op