Lutetium

Personally though I would suggest going with an ego Frosted Borealis Hammer and an Avon shield, upgrading to a Divine Shield when possible if you're super serious about melee on Elf to activate the bonus 7% crit damage and 30% dura use reduction since you can't hold 2 hammers or 2 Celtic Royal Knight Swords, it maintains the 1.1x charge damage boost the same as Avon as well.

You get double bash since Borealis is normal speed, higher max than CRK, about half the repair fee, and much better erg upgrade (50 min/max, 25 all defenses, 8% auto defense, and a quite considerable 25% cooldown reduction to (non-race exclusive but Elf doesn't have any) close combat skills.
Frosted Borealis Hammer will end up with 173 max displayed on the weapon if crafted by a GM dan 3 smith on smithing talent that gets the max bonus from the minigame after upgrades+erg, blunt mastery boosts that by another 30 vs sword mastery's 20, 5 points into both Spirit Training and Spirit Control will net a further 40 max damage netting 243 max before even enchanting it or reforging. 1H R type bonus is lower at r7 only 50% compared to 2H R type giving 74%, but ego will give 15% regardless of weapon type so you can still get a solid +65% crit damage with your hammer, 72% if you manage to get a hold of a Divine Shield.

So considering the 2h Celtic hammer/axe can't double bash, Life Exploration rod can't get special upgrades, and Soluna is out of reach reasonably, Borealis Hammer is really the way to go on an Elf in my opinion. I didn't mention that ego can boost bash's multiplier by 20% (additive) and one of the ultimates is 50% to recover 10% hp (not wound) from any close combat skill use which helps make up for elves having lower base defense and lower str/will caps for added defense/mdef.

Some extra final notes, you can use Broken Horn Hunter helm+glove+boot to get a full 10 points of smash enhance to boost that by 1.15x, and normally reforging a 1H limits you to a max roll of 10 for smash damage, but you can bypass this by rolling a higher smash damage line on a Red Echostone (if you roll 20 level on a grade 30 echostone and have smash enhance set on you'll reach 943% smash multiplier with dan 3 using 1H or 1012% if you roll smash 3 on two accessories ontop of that) and using your hammer's reforge slot to roll for max damage 10 (+20) instead or charge damage 10 (+15% additive to base multiplier per level, 10 level will more than double the damage from dan 3 charge on Elf and Human making it a more viable skill to use, particularly with cooldown 20 on helm to reduce it to 5 seconds, 3.75 seconds with erg 50 hammer's cooldown reduction applied on top of that, or maybe 2.5s if erg is applied before reforge I haven't tested this yet so I'm unsure the order.)

It would be nice to see another tree or two of 3 stage combos added for sure, especially with so many monsters being immune to pummel, the strongest multiplier skill at fighter's disposal. Admittedly though, if you're a giant the extra cooldown reduction from combo mastery already lets you chain all 6 skills infinitely, so long as you can actually use pummel on something, although that's a bit less the case if you're using knuckle ego with 1.5x stage 2/3 speed, but erg also patches up the problem with another additive 50% cooldown reduction.

That's Devcat's way though, they've been refusing to touch skills due to player outrage in the past over dynamic combat and instead just make bandage "rebalances" via new upgrade systems and weapon tiers (special upgrades, pierce on 2h sword and bow, easier set effect access with points on weapons, erg, Revenant/Perseus special set effects, new egos) which people oddly seem inclined to dismiss as "power creep" instead of recognizing that balance is now walled behind upgrade systems instead of patch updates then wonder why new content is "too hard".

I expect thats how they'll address Respite too, if they bother at all, an upgrade or enchant that just adds to it's healing rate, which will in turn also become outdated as player characters continue to gain stats as more skills are added, recreating the problem instead of simply fixing the base skill in the first place.

All that being said though, I'm pretty happy with my ego Revenant knuckles, piled up with my reforges (charging cdr 3, combo 9, somersault 16+dropkick 18 on the same shoe) they've been pretty effective already even at only erg 30 without any cooldown reduction, if the cd reset rng is bad I'm just going to smash with my borealis or chain impale a few times depending on what's equipped since I'm not locked into the knuckles only or anything.