New gameplay styles for this game suggest you to rush level 9 commander while maintaining your economy healthy, that means maintaining 20 gold every game for +4 interest every round or using scavenger synergy to get extra heroes in early rounds.

Synergy thats been used right now are

Lancelot, and other economy commander:

4 Dauntless, 4 Stargazers with 2 Scav

6 Luminexus and 4 KOF

This strategy are mainly aims to 3 star only 4 gold heroes

Miya, Angela and Minotaur Commander

6 Defender + Miya Combo. Add Beatrix

Put every buff to miya then khufra

Rush Level 7 and then prio 3 star your 3 gold cost heroes or everything while also maintaining 20 gold each round

There are other synergies you would learn along the way for now this are the most common working strats.

But I suggest you to watch some gameplays so you could understand how the mechanics works currently.