(Please Help) NTH load balance-failover VS ECMP load balance-failover

I’m currently comparing load balance and failover with nth method and ecmp method, I have some questions:

  1. When I run failover in nth load balance, I try disable the ISP that I used but the connection doesnt move automatically, instead I need to make a new connection so I could connect to the backup ISP, does this happem bcs of the connection-mark in nth?

  2. Many references say that ecmp load balance has a failover effect so we dont have to configure the Distance on the default route we use, why it could happen? How could ecmp load balance has a failover effect without setting the Distance parameter?

Any answer could really help, thank you

Please anyone I need this for my final project in college