S!Sharena +HP -Atk still useable

She can't compare with Soren if you have him merged, but she still provides a lot of utility to a team. Her chill works perfectly against tanky units, as it debuffs atk/res based on the lowest speed on the enemy team, so you can pair her up with a strong red magic nuke or a red dragon and turn her into a dedicated support and blue check maybe?

Her base A-skill or fury + lancebreaker or something like that. It's simple and effective. She won't be fighting too much, because she will function as a support. Fury ups her resistance, which allows her to use ploys as well at 36 res. Her damage output won't be mindblowing by any means, but she definitely won't be a weak point of her team.

Or just give her gronnblade. She has enough speed to pull it off, but she would just be a worse Nino.

You could give Soren her Swift Stance and pretty much turn him into a better version of your Spring Sharena