BIRD over internet with static routes?

[dan]

I'm wanting to use BIRD to monitor WAN connectivity of CLIENTS to a SERVER.

I'm not familiar with BIRD and I'm relying on RFC5883 description of
multi-hop to make my case.

I want to set 2 static routes.  1 is a route from CLIENT to SERVER out
WAN1.  This is the route to be monitored by BFD and it's route
distance is 1.  The second route is the fall-back, it's not monitored
and it's distance is 2 out WAN2.  BIRD/BFD's job here is simply to
tear down the static route with distance 1.

Complication, client's are likely dynamic IP address and also likely behind NAT.

The net result is to have a VPN such as wireguard migrate from WAN1 to
WAN2 rapidly on WAN1 failure.  Wireguard is built to handle this, so
ignore complications from changing of src addresses, they are handled.

Is this doable and if so, can anyone offer any help with the config?

Thanks!
Dan.