Yep, it is a lot going into one build, and it doesn't scale well. I'd go Fighter 16/Ranger 4 (maybe ranger 3/rogue 1), but it is a lot at level 8. 

Actually, there's no limittion to the amount of offhand attacks you can perform in a single turn, meaning that you can do an extra dual wield attack for every attack you perform unless the description specifically states that you can't, a prime example being Haste. Therefore, you get 10 attacks with Extra attack, action surge and two weapon fighting at level 20, add one if you have haste active, and as an echo knight, you use unleash incarnation, you can perform 12 total melee attacks using a one handed light weapon.

Quote from Saijin_Shadowblade >>

Actually, there's no limittion to the amount of offhand attacks you can perform in a single turn 

Per the PHB:

Two-Weapon Fighting

When you take the Attack action and attack with a light melee weapon that you’re holding in one hand, you can use a bonus action to attack with a different light melee weapon that you’re holding in the other hand. You don’t add your ability modifier to the damage of the bonus attack, unless that modifier is negative.

If either weapon has the thrown property, you can throw the weapon, instead of making a melee attack with it.

You can only make 1 offhand bonus action attack per turn.

And to be fair the Fighter 11 feature should be called Extra Extra Attack and Fighter 20 should be Extra Extra Extra Attack so there's less confusion about Extra Attack stacking.

Man, as a person who plays mainly fighter, I have no idea how I haven't noticed that it requires a bonus action. Thanks for telling me. Still, 8 attacks is a lot.

Anyway, I'm gonna go back to designing a level 5 Samsung Smart Fridge Tempest Sorcerer.

For the build the OP was going for, Fighter 16/Ranger 4 (from their last comment). Assuming they went Echo Knight and Gloomstalker Ranger, they'd get:

1. Action Attack
2. Action Attack
3. Action Attack
4. Dread Ambusher Attack (round 1 only)
5. Unleash Incarnation Attack (CON times per long rest, made from echo's position only)
6. Action Surge Action Attack (once per short rest)
7. Action Surge Action Attack (once per short rest)
8. Action Surge Action Attack (once per short rest)
9. Bonus Action Attack (made with 2nd weapon in offhand)

I know Haste gives at least 1 more Hasted Action Attack.

I'm a bit fuzzy if Haste would give a Hasted Action Surge Action Attack. 

Would Action Surge Unleash Incarnation Attack be a thing if you had a 2nd use of that feature?