Titan team…
I still use Wu hitting 14* titans. Yes he’s squishy but attack boost, when he doesn’t miss makes a difference. I also take Wilbur, who is gold for survivability. A hero to look out for at the next Atlantis Rising.
I would focus on your 3*&4* heros and leave your 5* heros because they are so expensive. Great advice throughout the forum.
If you’re not already in one, the best advice I could give you is to join a good training alliance. Check out Alliance recruitment, there are many.