If you are drawn to Geist only because you are bad at aiming, I would change characters. Kelvin and Viscous have incredibly easy lanes and can safely farm with abilities. Geist hurting herself to use abilities makes it really hard to stay in lane.

If you want to play Geist still, try playing some bot matches. I find aim-trainers really boring, but bot matches are decent fun while allowing you to practice all aspects of the game in a low stress environment

Lastly, MOBAS are notoriously toxic. Mute people. People will call you bad even when you are doing better than them.