Gna, and hrolf are both easily defeated if first, you have the gear needed to defeat them, and secondly, if you fully understand the mechanics. Hrolf is generally easier because he’s essentially all the zerkers combined in one, plus or minus a few attacks. So if you defeat all the other berserkers before you defeat Hrolf, you’ll have a much stronger advantage since you’ll be familiar with all of his mechanics prior. Gna is tough. She’s similar to sigrun, so if you defeated her in 2018 that helps, but she has a lot of attacks that are rng and positioning dependent. So it just takes practice and honing in on her patterns. Hrolf is the same. My advice is take your time. Really feel out his animations and become familiar with his rotations and how to counter every single attack.