It’s possible to make him as such, but you’re probably gonna want to invest in both his speed and resistance because his prf weapon deals with his speed stat. The problem with that, however, is that a lot of the commonly used mages can reach his speed, or even higher, due to the speed powercreep (L!Celica for instance).
To counteract this you can run a Chill Spd support unit on your team. It’s not a foolproof plan because it only targets the unit with the highest speed stat, but it can help if you’re able to push him far enough (thanks to his ability to move three spaces). Just know that he’ll also be targeted by Chill Spd and other such debuffs unless you’re running someone on the team with higher speed.
Another thing is that Vantage isn’t really that good on him. His attack isn’t that high to really make use of it, especially when we start getting into merges, buffs, debuffs, etc. You’re probably better off running Quick Riposte to be honest.
Even with all of that though his ability to tank and kill mages will still be fairly… mediocre.
It’s probably better to run Distant Ward for his A skill. He can’t take on archers anyway its dagger units aren’t too common at the moment unless they’re player controlled (and I don’t think Leila is gonna change this too much). More attack and resistance will serve him better in this situation.
Change the B skill. He’s not that good at Vantage and, like you said, other units do it better. Quick Riposte/Guard/Mystic Boost/Dull Ranged are all decent to use for him.
Seal can change. Swift Stance, or Darting Stance, can help with his tanking.
As a frame, this is probably what it would be. Just fill in the rest as needed. Of course I dunno what fodder you have, so…
Also note that these are simply my opinions, so don’t take anything as more than that, lol.