WireGuard - load balancing two different provider

[sindy]

How to load balance it? So two would be active - let’s say that provider A is preferred but if that link is not working it pushes traffic to provider B, when provider A is back it pushes route back to provider A.

The behaviour you describe is not load distribution but mere failover.

But leaving that aside, the task of failover/load distribution between two Wireguard (or other VPN except bare IPsec) tunnels is exactly the same like the task of failover/load distribution between two WANs with NAT, and for that there are multiple recipes here on the forum, like this one.