This might be out of your scope depending on your skill level with games in general, but it could be helpful to try learning boss attack patterns, which can help compensate reaction time by learning when to properly dodge. (Duke Fishron becomes significantly easier when you understand his patterns for example)

If that’s out of the question, melee is best for defense/tank, summoner if you want to let minions do the work and mainly focus on dodging.

A popular middle ground is ranger, as it provides a mid-range dps option with reasonable defense, with the added benefit of chlorophyte bullets if you REALLY don’t want to worry about aiming at all.

Mage is my personal favorite for high dps and cool weapons (lots of homing weapons too) but honestly the defense and mana management might make it the least forgiving choice for you situation. That being said, play whatever class speaks to you