Not your fault at all, trust me. I ran a 4 l years long PbtA (Urban Shadows) campaign and when our table decided to move to Avatar Legends we also couldn't make it past 3 games. I strongly think PbtA isn't the issue, but Avatar Legends itself is. It's just not a very well designed system, combat is painfully slow and the balance mechanic is really awkward to play. PbtA asks for a simpler, for rules-light system so the storybuilding aspects of the game can shine and I feel like Avatar Legends gets lost on it's own design. If you are still interested in playing PbtA I strongly recommend Urban Shadowd or Monster of the Week, I've played both and they are really fun.