"Under the assumption of 2 other players at the table besides me. Is there a significant or near none EV gained from spreading 2 x $400 to 3 x $400.
If the EV gained is near to none, then I rather just stick to 2 x $400 and lower heat risk and all that jazz."

Since, yet again, NO ONE has either addressed or answered your question, I will. (Note to others: He has all the money he needs. He's bumping into the table max. He doesn't care about optimal number of hands or Wong's numbers, or ROR, or anything else that you insist on babbling about. Now, may we move on, please?)

To the OP: With two other players, and playing 2 x $400, you need to also consider the dealer has a hand, too. So, that's a total of five hands at the table. If you spread to a third hand of $400, that's six hands, or an increase of one hand in five, or 20%, and not the 25% that you stated in your OP. Meanwhile, you're increasing your bet by a whopping 50% ($1,200 instead of $800). So, from an e.v. point of view, extra risk be damned, you're much better off with the third hand.

And THAT -- and only that -- is the answer to the question!

Don