What's next?

Congratulations on completing the game at SL1. I hope you have learnt how to effectively deal with most if not all bosses in the game. Here are other ideas for your next SL1 run:

1. Dual wield any weapons that you can properly wield one-handed. For example, dual wield Broken Straight Sword x 2 or some other daggers. If you want to do a dual wielding run of a particular weapon, you might as well collect/purchase/farm multiple copies of the weapon and infuse each with a different elemental stone. Then move to the next NG cycle for your SL1 dual wielding run.
2. Do an SL1 run with no infusion, buff, or upgrade of your weapons. Any weapon you use must be at +0. For example, you are not allowed to upgrade your swords or bows. Your weapons must not be infused with an elemental stone and you are not allowed to buff a weapon with a spell or an elemental resin.
3. Get to NG+7 as quickly as possible and do an SL1 run at NG+7. Do multiple any% runs to get to NG+7 as quickly as possible, defeating only the mandatory bosses. The game does not get any more difficult beyond NG+7.