D&D General Miss at Most Once per Duel with Studied Attacks, Elven Accuracy and Vex?

[Silam]

The Fighter’s 13th level feature seems under-discussed… (or perhaps under-studied?)

Level 13: Studied Attacks​

You study your opponents and learn from each attack you make. If you make an attack roll against a creature and miss, you have Advantage on your next attack roll against that creature before the end of your next turn.

This, in combination with Elven Accuracy and a Vex weapon seems quite strong.

1. If you miss, Studied Attack gives you advantage.
2. If you hit, then Vex gives you advantage.
3. And if you have advantage, Elven Accuracy almost guarantees you’ll hit again, and hence go back to step 2.

This is an at will combo. There are no expendable resources involved at all. The one drawback is the advantage sticks to a single enemy only, so it’s effective against a strong boss, but not against mobs. I was originally going to title this thread "Miss at Most Once per Combat" but then renamed it to "per Duel" because of this non-transferrability of the advantage across opponents…

13 levels in a class is a big investment for any build, but it’s not like the Fighter is a slouch either way. By then you also get the 3rd Extra Attack and many other goodies.

Maybe this is so obvious that’s why it’s not discussed much, but I just thought I’d bring it up

Anything else worth considering to add to this mix, or to substitute for of one of these ingredients?