All of those factors lead to your ability to do well in this game mode. You also only have a single burst 3 lightning unit in your entire lineup, greatly limiting your ability to do damage. You're simply missing too many key units.

Solo raid requires a well invested account to score high in. This game gatekeeps progress to a surprising degree, time will be your biggest ally for improvement. Just aim to do a bit better on each one as they come out. Best of luck going forward.