Hi ,
welcome to Rune Audio.
Your Ralink RT5370 should work on RuneAudio (RP2/3).
Please try to disable the internal wifi by modifying
/etc/modprobe.d/disable_rpi3_wifi_bt.conf
##wifi
blacklist brcmfmac
blacklist brcmutil
##bt
#blacklist btbcm
#blacklist hci_uart
After this disable the wlan1 service
systemctl disable netctl-auto@wlan1
and reboot.
Also check the debug output and journalctl for errors.
Frank