Just reroll an account on the side while playing that one until you draw something you like. If you're not enjoying the game because of struggling to clear content then there's no point of playing but do note that you don't need SSRs to clear the content you seem to be struggling on, putting more time and effort into your weapon grid would most likely solved that. My alt account (a very messy dark team) is more likely weaker than your light team and I've been able to clear many ultimate advents with it, I just do it for the jewels and ignore the account for the rest of the event unless I need to spawn raids.
Though just be aware that you're giving up on a very good event hime and rerolling a new account doesn't ensure that account will draw any more SSRs aside from your starting draws.