Use different wpa_supplicant files in How to set up networking/WiFi describes how to setup networking to use different wpa_supplicant files for each interface.

Your etc/network/interfaces should work (only because it causes dhcpcd to disable itself), however this uses old Debian networking, which is far less robust than dhcpcd

There is no guarantee which interface will be assigned to wlan0/wlan1 due to a race condition (although the onboard WiFi will probably win). To be sure you should enable Predictable Network Interface Names (this is used by most modern Linux OS).

Use different wpa_supplicant files in How to set up networking/WiFi describes how to setup networking to use different wpa_supplicant files for each interface.

Your etc/network/interfaces should work (only because it causes dhcpcd to disable itself) and can be configured to use multiple wpa_supplicant files, however this uses old Debian networking, which is far less robust than dhcpcd

There is no guarantee which interface will be assigned to wlan0/wlan1 due to a race condition (although the onboard WiFi will probably win). To be sure you should enable Predictable Network Interface Names (this is used by most modern Linux OS).