I'm Eastern Orthodox!

Great! So is a fellow mod account at c/Christianity. As a covenant Christian, I sympathize; previously I had trouble being sure of your foundation. Will factor in. You might like a long excursus attempting to have the Five Points interact with Orthodoxy.

Background: No sola is wholly "alone". The Orthodox use the big picture, and it ought to encompass two aspects, the realm where faith operates "alone" (as Catholic Bibles said before Luther), and the realm where faith and works operate together. All five solas have this duality.

it's not just faith alone, because true faith is always proven in deed (which has always been the teaching of the Church)

... over the operation of a whole life. (Granted, Dismas's works were scanty, Catholics credit him "desire of the laver".)

faith alone is salvific

... in the past-salvation event of regeneration. Two different applications. Better than doubling down is taking both sides of an apparent paradox.

Because Orthodox see the big picture of three tenses of salvation, it's easy to neglect that Protestants often use the word salvation to refer only to regeneration, a past event. You acknowledge the big picture in very good language; then you add "Protestants who claim to be saved lack humility", but more accurate would be that they lack consideration for the C & O use of the word "saved", as many don't intend to offend sanctification or glorification. They do claim to have assurance given directly by God, and I'm not aware of a Church teaching that assurance is impossible, only that it's so rare that Protestant broad proclamation of assurance is irresponsible. But when the Lord says "Thy faith hath saved thee" (Luke 7:50, 18:42) I don't think he was limiting that to the past, but speaking of the big picture.

grace is uncreated and given through participation in the divine energies

Yup, present-tense grace manifested in sanctification aka present-tense salvation. Protestants pretty much limit their energy intake to a crumb and a thimble (Swift called them Aeolians for airiness), but I think God still counts enough of them.

[I try to be careful with quotes, and, since Athanasius didn't contend with Shirley MacLaine but we do, I note that he said, "Autos gar enenthropesen, hina hemeis theopoiethomen" (Incarnation 54.3). Nowadays I might translate that "be defied" rather than "become god", in the sense the Bible calls "partake of divine nature". Otherwise Americans get bad ideas about theosis.]

I don't think people who haven't found need for Palamas are necessarily prevented from "participation in God". If it means filling up in our flesh the afflictions (and greater works) of Christ, we've got it. We're members of his body, like hands and feet. We don't reject synergism except in the act of regeneration, which is logically only God's because the dead do nothing. However, I realized the Reformed teach simultaneous monergy and synergy: in one sense only God revives, but in another sense God gives and we receive (passively). Reformed are busy fighting neo-Pelagians so they play down that synergy, but it's there.

"Legalism" is defined as justification by works, not faith. You're saying justification by faith is "legalistic" because it's a "declaration" (imputation) of righteousness. Transformation (infusion) does indeed follow. We say, we are deemed, and truly are, righteous. Under "soteriology", OrthodoxWiki says theosis "rejects that salvation is a positive result to a legalistic dilemma", preferring healing metaphor; that sounds unnecessarily casuistic and semantic. But at "theosis" it admits past tense "we have become ... partakers of divine nature." So is there something wrong with declaring this past event more rigorously?

treats faith as a formal abstraction and not as a personal relationship with the living God

That's not sola fide, it's false assurance; yes it's a real risk. Modern Protestant evangelism presses hard to emphasize faith is not just knowledge and the pressure of assent, but also personal trust; and trust is a transforming (and, by grace, permanent) relationship. None can snatch from the Lord's hand; he may remove his candlesticks (lights of organization in community), but I don't believe he removes those people he has once laid hold of. If someone doesn't show grace in the present, he doesn't show he really had trust in the past. I absolutely agree that some tent-raisers became obsessed with collecting signed cards and doing little to build relationships among the signers; that did some good and some harm and their view of the balance probably differs from mine. I absolutely agree that some 501(c)(3) orgs are selling good feels in exchange for showing up for an hour once a month and doing nothing (or, for paying cash). But this is an error that Protestants are tempted to, just as C & O are tempted to their own errors; it's not the Protestant theology that's at fault.

Your last paragraph is thus a criticism of those who take one side and fail the other, but not of mainstream Protestants. I'll leave you with Hannah Smith's observation that people get very confused over this theology until they realize there are really two sides, one in which God does everything, and one in which we and God do everything. When you really get to participation and the loss of your own life, you see why these two both operate without any contradiction, and since I trust you on that I won't elaborate.