I would love to know the most time efficient way of getting to hero level 150
If you really want to get the Bastion rewards as soon as possible then the best method is to simply 1 trick him in Quick Play or the Arcade. Usually I wouldn’t recommend 1 tricking Bastion in competitive but you could get away with it in this season because he is very strong right now.
Personally I am only playing Bastion in QP/No Limits because I really want the “War Machine” title at level 50. It sounds pretty cool. I’m level 34 on Bastion right now.