Fantenberg and Benn gave it the ol' college try and they weren't making bad mistakes, but there just isn't enough talent-- a career #7 and a career #6 who had a rough start and lost his lineup spot to the #7. Plus, they're not really a good fit as both are competent third-pair defenders in their own zone but aren't good enough in transition and provide no offensive spark whatsoever.
Exactly this. Fanta and Benn are decent with in-zone play, the problem is they're always there. They just don't have enough puck-moving ability to transition up-ice and get offensive zone time. I think Fanta had like 11% xG. By eye I thought he and Benn made good separations in the D-zone and timely blocks, but you can't spend every shift there, getting a chip-out, and be back to defending.
Edler breaks down and becomes fatigued with heavy usage. You could see it happening the more minutes he played, just started looking slower. I'm a Stecher fan but he's just overmatched in tough minutes too.
I'm the furthest thing from a Myers fan, but they do miss him. He can play 20 minutes and is actually a solid transition defenseman from the D-zone out. His range and skating are a big advantage over Benn.