The grammar dictates what "this" points to. It can't point to salvation, because the grammar does not allow that. You're suggesting that the verse says, "For by grace you have been saved through faith. And this [saved] is not your own doing." That's stupid. It's equally stupid for "this" to refer back to "grace". That makes the verse "And this [grace] is not your own doing; it is the gift of God". That interpretation makes the verse needlessly redundant.
The only way "this" can point to salvation is if the verse read "For by grace you have salvation through faith. And this [salvation]".
But that's not how the verse reads. The verse reads "For by grace you have been saved through faith. And this [faith] is not your own doing;"
Sorry you have no ideas what you are talking about. You have no understanding of Greek grammar and many Greek exegetes reject your claim.
Through faith (δια πιστεως [dia pisteōs]). This phrase he adds in repeating what he said in verse 5 to make it plainer. “Grace” is God’s part, “faith” ours. And that (και τουτο [kai touto]). Neuter, not feminine ταυτη [tautē], and so refers not to πιστις [pistis] (feminine) or to χαρις [charis] (feminine also), but to the act of being saved by grace conditioned on faith on our part. Paul shows that salvation does not have its source (ἐξ ὑμων [ex humōn], out of you) in men, but from God. Besides, it is God’s gift (δωρον [dōron]) and not the result of our work.
A.T. Robertson, Word Pictures in the New Testament (Nashville, TN: Broadman Press, 1933), Eph 2:8.
The words, “through faith” speak of the instrument or means whereby the sinner avails himself of this salvation which God offers him in pure grace. Expositors says: “Paul never says ‘through the faith,’ as if the faith were the ground or procuring cause of the salvation.” Alford says: “It (the salvation) has been effected by grace and apprehended by faith.” The word “that” is touto (τουτο), “this,” a demonstrative pronoun in the neuter gender. The Greek word “faith” is feminine in gender and therefore touto (τουτο) could not refer to “faith.” It refers to the general idea of salvation in the immediate context. The translation reads, “and this not out from you as a source, of God (it is) the gift.” That is, salvation is a gift of God. It does not find its source in man. Furthermore, this salvation is not “out of a source of works.” This explains salvation by grace. It is not produced by man nor earned by him. It is a gift from God with no strings tied to it.
Kenneth S. Wuest, Wuest’s Word Studies from the Greek New Testament: For the English Reader (vol. 4; Grand Rapids: Eerdmans, 1997), 69.
For by grace, etc. This may truly be called exceeding riches of grace, for ye are saved by grace. Grace has the article, the grace of God, in vv. 5, 7.
And that. Not faith, but the salvation.
Of God. Emphatic. Of God is it the gift
Marvin Richardson Vincent, Word Studies in the New Testament (vol. 3; New York: Charles Scribner’s Sons, 1887), 376.
and this (not your faith, as Chrys. οὐδὲ ἡ πίστις, φησίν, ἐξ ὑμῶν: so Thdrt., al., Corn.-a-Iap., Beza, Est., Grot., Beng., all.;—this is precluded (not by the gender of τοῦτο, but) by the manifestly parallel clauses οὐκ ἐξ ὑμῶν and οὐκ ἐξ ἔργων, of which the latter would be irrelevant as asserted of πίστις, and the reference of ver. 9 must therefore be changed:—but, as Calv., Calov., Rück., Harl., Olsh., Mey., De W., Stier, al., ‘your salvation;’ τὸ σεσωσμένοι εἶναι, as Ellic.) not of yourselves, GOD’S (emphatic) is the gift (not, as E. V. ‘it is the gift of God’ (θεοῦ δῶρον),—τὸ δῶρον, viz. of your salvation:
Henry Alford, Alford’s Greek Testament: An Exegetical and Critical Commentary (vol. 3; Grand Rapids, MI: Guardian Press, 1976), 94.