Re: Routing and Dual WAN
PBR is a static route with conditions. FQDN is not allowed (I guess it's because NOT static) in static routes.
Although I haven't tried myself but as long as you set the same default routes to both wan interfaces, then set the first policy for the FQDN dst to the second wan, and the second policy for "all" destinations to the original interface, I think it would work as you intend.
Try it to see if it works. If not, you can always to go SD-WAN.