Honestly just do your dailies and the evening events like 9tails invasion. No rush on leveling up.

All XP sources for the day (some are level locked / only certain days): Cat Quiz, daily practice, Experience Treasure, instances (with spare stamina, don't use pots), 9tails invasion, Ninja Exam, Ninja Test, Rescue the Jinchuriki, Space-Time, Team Instance, and Wanted Missions.

If you have quick questions like this, recommend the official Discord strategy channel.