On the Switch, the RetroArch front end uses a core called fba2012 or fbneo. Users often utilize "FBA Next" style ROM packs here because the Switch's Tegra processor handles the FBA architecture very efficiently, offering better battery life and performance than trying to force a full MAME core to run.
If your FBA Next Pack is not working, check these common issues: Fba Next Pack Roms
Tools like ClrMAMEPro or ROMVault can rebuild a known-good FBA ROM set from a complete MAME set. You’ll need: On the Switch, the RetroArch front end uses
This is technical but ensures perfect compatibility. Missing BIOS Error: