Penacony set without ice characters?

So I’ve been seeing a lot of posts on here about how necessary the 2Pc Penacony set is due to the 5% ERR but is that really the best move if you aren’t using any ice DPS on the team with her? I’m planning on running her with Kafka teams and Topaz teams which don’t use any ice dps so I feel like the secondary effect gets wasted and that it would be better to use FotA or Broken Keel instead depending on which team I’m running. Also I’m going for E0 and only have S2 memories so is it even worth aiming for the 3 turn ult that this sub praises so much?