I have the exact same problem. I’ve been able to get past the secure origin issue.
After that auth0 makes chrome browser to handle the authentication.
Which switches from the app to chrome.
Doesn’t get back to the app after authentication, but continues on the chrome browser instead 
.
To make it get back to the app, I’ve tried using intent-filter, which gives a pop up asking to continue on browser or the app this time.
But still choosing browser works fine and choosing app gives a blank screen.
This guy seems to have gotten past this redirection issue too. How to prevent First Party App Consent when using Auth0 + Ionic + Capacitor
Although he’s using iconic I can see that the problem is same and might work for me.
Let me know if you intend to continue with Quasar Capacitor and I’ll tell you what I did to get past the secure origin error.