What is the best and fastest way to level up in ventures, as a solo player?

I dont have any friends that play save the world and no one ever joins my lobbies, i join random lobbies but I dont get much xp. I am trying to get a recruitment voucher, because I dont have many good heros, and I am trying to get a good build so I can move onto twine peaks (stuck on canny currently.) I need help, i am currently level 11 on ventures.