SD-WAN Traffic Routing

 We have one MPLS and one Internet circuit connected to WAN 1 and 2 on the FortiGate firewall.
We can reach the internet using both MPLS and direct internet. Direct internet is preferred path to the internet as opposed to traversing MPLS
Via the inside interface on the FortiGate we have BGP peering from the FortiGate to another router

I could setup a SD-WAN rule which load balances internet via WAN 1 and WAN 2.
Have a second SD-WAN rule which forces MPLS traffic out e.g. WAN 2 MPLS

Its the BGP peering via the inside interface that we don't want to route via WAN 1 or 2. Does this mean that we shouldn't setup SD-WAN and just utilize routing to direct traffic out the correct links?

TIA :)