Do I need to restart my run?

I think I've ruined my first run. I'm currently facing Ketheric in an area u can't fast travel away from and am massively underpowered to face him. I've made dozens of attempts and cannot defeat both stages of the fight (Murkle crushes me).

I've also just discovered I've missed two important companions ENTIRELY (Lae'Zel and Wyll).

What's should I do?