I think I might have ruined my run

Last week I finally decided to buy Chapter 3 and 4, so I decided to replay everything from Chapter 1. I wanted to go with a 100% Pacifist route, sparing everyone and not FIGHTing a single time. Everything worked out fine, until near the end of Chapter 4, where you're forced to fight a Titan. The roaring knight fight in Chapter 3 also can't be spared, but that fight was optional. I ... did not know about this, so I sold every weapon that I got to buy amors and healing items. I also only equipped amors that increase as much defense as possible, and selling all the ones that give attack stats. Now my attacks do virtually no damage, and I don't know what to do. Should I start everything all over again? Or try to plough through? I'm not good at dodging bullets genre, and I have heard people still failing after 20+ attempts.