-Our hand has to have 50%+ equity against opponent's ENITRE range
Can you please give a source where you learned it?
Imo it cant be enough to have >50% equity vs entire range, because once we get called, vs his calling range we will have <50% equity which means it is a losing play?
Imo it is also not enough even to have e.g. 55% equity vs villians calling range, because we are not going to realize our equity, will be raise % of time and have to fold, or will have to fold vs turn and river agression especially on bad runouts (and with hands that have only about 50% equity mostly many cards are bad on turn and river).
For example, we might have 22 which has 55% equity vs entire range of villian, but the hand has bad playability, which is why I think we cant purely look at equity of the hand.
(bluff freq%*opp bluff bet - Bluffs Eq*river pot)
Here you just consider villian will bet turn and check river, but what about his implied odds once he hits his e.g. top pair, or when he bluffs again river and you plan to fold any river card? Imo these two factors which you mentioned are very tough to calculate and decide for it, especially because all we know about frequencies of opponent is pure assumptions.
(equity foldrange*flop pot)
For this one, it is calculated as we play on river and it villian checks behind. What about his postflop frequencies, and implied odds? I find this comparison totally innacurate.