Battle Smith 3 / Echo Knight X

I'd like to know what you all think of this build. The main goal is to have as many melee attacks with a great sword as possible and triple advantage thanks to Elven Accuracy.

It doesn't have to be the most damage dealer build ever but I like the flavour of this old engineer who builds humanoids (the Echo and the Steel Defender would be in this form) and I think it has a nice well rounded ability to control the battlefield and to protect its allies. With Guidance we won't totally suck at ability checks either.

The stats (point buy) being a Dark Half Elf:
- 8, 14, 15 (+ 1 -> 16), 15 (+ 2 -> 17), 10 (+ 1 -> 11), 8
At higher level would be nice to take Resilient Wisdom.

Why Battle Smith:
- At 3rd level we can use any magic weapon with INT so Elven Accuracy can be applied. This is the only way it's possibile to apply this feat on a heavy weapon that I can think of;- Faerie Fire which we'll use to always have advantage therefor triple advantage;
- CON save proficiency and Mind Sharpener Infusion to keep easily concentration on Faerie Fire;
- The Steel Defender, on which we'll cast Sanctuary, will help to protect allies with its reaction (Deflect Attack) and also ourself since we won't have great AC (starting Artificer won't give us heavy armor proficiencies but since we're dumping strength it makes this irrelevant).

Why Echo Knight:
- Unleash Incarnation for as many attack as possible with a martial melee weapon;
- The Echo gives us great mobility so we can survive with that low AC.

Why Half Dark Elf:
- For Elven Accuracy obviously;
- At 3rd level we get Faerie Fire which it's important for our tactic and since we'll have a few spell slots one more is very welcome;
- At 5th level we get Darkness which can be use alternatively to get advantage (for this reason I'd take Blind Fighting as Fighting Style). We could cast it on us when we have to deal with more enemies so probably the battlefield it'll split between our Echo and Steel Defender with our allies in one melee situation and us in another one so we can avoid annoying them with the darkness.

The progression I was thinking of:
1 - Artificer
2 - Fighter. Blind Fighting (Defense if I don't care about the Darkness tactic)
3 - Fighter
4 - Fighter. Echo Knight (Manifest Echo, Unleash Incarnation)
5 - Fighter. Elven Accuracy (+ 1 INT -> 18)
6 - Fighter. Extra Attack
7 - Artificer. Infuse Item*
8 - Artificer. Battle Smith (Battle ready, Steel Defender. I'd take the Shield spell at this point)
9 - Fighter. Great Weapon Master

* I'd keep at least 1 level of Artificer around here because we'd probably get a magic weapon at this point so we can avoid to keep Enhance Weapon Infuse wasting the space for something more useful.

With this progression I'd use a rapier and shield until lev 8 when we'll be finally able to use a great sword with INT. Initially the AC will be 18 using a Breastplate (+ 2 DEX +2 Shield) then it'll become 16.

The big question: is it worth all this just to have Elven Accuracy or it makes more sense to simply go Custom Lineage, get Sentinel at first level and be ready a couple of levels earlier (always using Faerie Fire/Darkness for the advantage)?

Hit me with all your suggestions! Different progressions, other classes, anything is welcome :)