Eliwood.

I've used Darting blow on hom at 5* with the exact same IV spread. It works alright outside of Horse emblem but I switched to Fury because he was getting doubled a little more often than I liked. Fury also helps him capitalize on the Atk Ploy seal.

Edit: Actually mine is -HP. Also, Life and Death can get you the close to speed your looking for and also help you avoid those doubles.

I'd say wait for one with +spd and -hp if possible then give him darting blow. He hits 39 speed on attack then and is 33 for avoiding doubles. If you only use two horses and Eliwood gains a Hone Cavalry buff, he hits a massive 45 speed in attack with his legendary deathblow 2 weapon.

Here is a screenshot of my Eliwood before I deleted my
acc cuz idiot. -hp +spd is the best boon, with Darting Blow 39 spd by himself is awesome, I changed Axebreaker for Desperation and a Hone or Fortify of your choice. Eliwood was my juggernaut, and he can crush armies in Horse Emblem. Maybe if you have a repositioner to save him from Brave Bow users would be nice

Mine is +Atk, -Spd which puts him in the worst situation for getting doubled, but also puts him in the best position to 1-shot. He's running Death Blow 3 (Which does stack with Durandal 100%) and Swordbreaker 3. He can generally out-duel any slow axe user like Hector/Sheena, and the majority of sword users on player phase thanks to the double from swordbreaker. This is all without using a Horse Emblem team.

TLDR: Speed's not worth it unless you're running Horse Emblem. Speed should only be a problem outside of player phase (Which you shouldn't be using Eliwood for anyways). You have a +Atk Eliwood, just go all-in for the 1-shots.

Death blow should be preferable to further abuse Durandal's passive. On or off a cav team +10 attack if initiating is no joke.