WAN Limiter in pfSense
I am wondering if I could have one rule to apply over all the WAN to limit the whole bandwidth as I don't need to limit the bandwidth between the multiple LANs I have, any clue for that ?
Apply your limiter rule on the rule that allows access to the internet. Create rules that allow traffic between your vlans above this rule where the limiter is not used.
If you don't have any inbound connections then applying the Limiter outbound on WAN via a floating rule is commonly used. That then catches traffic from all internal interfaces.