Please try with one these :
sysdefault:CARD=V8237 VIA 8237, VIA 8237 Default Audio Device front:CARD=V8237,DEV=0 VIA 8237, VIA 8237 Front speakers surround40:CARD=V8237,DEV=0 VIA 8237, VIA 8237 4.0 Surround output to Front and Rear speakers surround41:CARD=V8237,DEV=0 VIA 8237, VIA 8237 4.1 Surround output to Front, Rear and Subwoofer speakers surround50:CARD=V8237,DEV=0 VIA 8237, VIA 8237 5.0 Surround output to Front, Center and Rear speakers surround51:CARD=V8237,DEV=0 VIA 8237, VIA 8237 5.1 Surround output to Front, Center, Rear and Subwoofer speakers iec958:CARD=V8237,DEV=0 VIA 8237, VIA 8237 IEC958 (S/PDIF) Digital Audio Output dmix:CARD=V8237,DEV=0 VIA 8237, VIA 8237 Direct sample mixing device dmix:CARD=V8237,DEV=1 VIA 8237, VIA 8237 Direct sample mixing device dsnoop:CARD=V8237,DEV=0 VIA 8237, VIA 8237 Direct sample snooping device dsnoop:CARD=V8237,DEV=1 VIA 8237, VIA 8237 Direct sample snooping device hw:CARD=V8237,DEV=0 VIA 8237, VIA 8237 Direct hardware device without any conversions hw:CARD=V8237,DEV=1 VIA Direct hardware device without any conversions plughw:CARD=V8237,DEV=0 VIA 8237, VIA 8237 Hardware device with all software conversions plughw:CARD=V8237,DEV=1 VIA 8237, VIA 8237 Hardware device with all software conversions
Don’t forget to stop retroarch (systemctl stop retroarch) before editing the retroarch.cfg. To start it again type systemctl start retroarch.
If doesn’t, try to run alsa-info.sh script and paste the output.