Interaction (regular interaction as well as fights) is heavily influenced by skills. So it isn't a requirement to just create a character that is able to blast away any enemies. You need more than just damage. Sometimes you want to hide or steal without being caught - sleight of hand wins, and every skill that is able to enhance your ability. Sometimes you seem to be overwhelmed by many enemies at once - you need to somehow disable the most dangerous of them to survive, then deal with the rest, then deal with the first. Spells can help with this. There are skills that boost your abilities in combat or weaken your enemies. This is often more efficient than try to directly blast the enemies away.
So a good way is to not just create one character that aims to do this all (which isn't possible) but create a party of 4 characters that all bring together a good set of different skills to be successful. You don't need to do it all alone, you're a party of 4 characters, 4 different classes, 4 different skill sets.
If you went most far with Sorcerer, try it again. Or if you found a different class that was not that bad, use that.
And this time look what you missed most in your previous playthroughs. What did kill you? What skill or feature did you miss to be successful? And from this, choose a different companion team. At level up, give your companions skills you previously missed in a fight.
And include the environment into your fights. You can push enemies into chasms to kill them. The cheesy bonus action "shove" might kill a powerful enemy if the terrain and positioning allows it. There are potent spells that push enemies around this way. You can throw grease, and your enemies get prone. Then hurl a fire bolt into the grease, and they're burning. At least in Act 1 and in the beginning of Act 2, there are so many barrels that explode if you hurl fire on them, you can blast them away with a cantrip. Initiate fights with ranged weapons and let your enemies waste their first turns by dashing into range. Make them run through grease and fire. Make them drop their weapons. Explore equipment looted and available from vendors that might add additional skills and see if there is synergy with your own skills. For example, your melee fighter might profit from a teleport skill to get in melee range fast. Much equipment adds "free" skills or "always prepared" skills you don't need to learn or provide spell slots for. If you see the game this way, every class is viable.
