Have a look at Issues with MP-BGP and IPv6 Link-local peers using extended next-hop - #2 by zero1three013, there is a reference configuration for Wireguard + BGP for extended next hop + IPv6 link local on DN42
Have a look at Issues with MP-BGP and IPv6 Link-local peers using extended next-hop - #2 by zero1three013, there is a reference configuration for Wireguard + BGP for extended next hop + IPv6 link local on DN42