There's tons, and tons, and tons of evidence pointing to this being Zelda 3 after 30 years.
I guess I should start with the big ones, the Master Sword and Calamity Ganon.
The Master Sword is literally rotting away.
Let me reiterate.
Literally rotting away.
LITERALLY ROTTING AWAY!!!!!!!
This almost completely rules out this game taking place ANYWHERE before ANY game that features the Master Sword, since it and the pedestal of time are in almost pristine condition whereas even the pedestal in BotW is broken and overgrown with foliage!
It seems the Master Sword has been lost to the ages and long forgotten, which Fits with the lore of the NES games and ALttP/ALBW
Quote from ALttP's manual, "The Sages first had to search for the Master Sword and a hero to use it." this strongly implies that even the SAGES had lost track of the Master Sword by the time ALttP rolls around (And no, Hyrule Historia just doesnt work with the canon of ALttP, so I don't tend to follow it in any capacity; however, I find this game being Zelda 3 works even by lowered HH standards). Given that ALttP was made as a direct prequel to LoZ according to both the US box and Japanese instruction manual, it would seem they originally wrote the Master Sword in in such a way they could explain why it is missing from NES Zelda, where the Master Sword is COMPLETELY GONE. BotW might even revolve around a quest for the Master Sword, with the Master Sword being an ultimate weapon found at the very end of the game (If it was midgame, what would be the point of giving Link Axes and Lances/Spears?), maybe along the lines of the Fierce Deity Mask in how it makes the final boss a cakewalk (It's been reported Ganon can theoretically be fought immediately after starting the game). The Master Sword is lost to the ages during the NES games, which fits with the Master Sword
Let me reiterate
LITERALLY ROTTING AWAY!!!!!!!
We see on the title logo the Master Sword is cracked and rusted, and in the trailer that the pedestal of time is overgrown and ruined, which is worse than it was even in ALBW and TP, which again indicates both this can not take place before a game with the Master Sword (unless someone did some serious restoration work) and it fits with the lore of being lost to time in the NES games. The game being a quest to locate the master sword (at least in part) and the aforementioned blade being the ultimate weapon would make Link's extended arsenal not pointless.
Calamity Ganon is built up to be completely inhuman, to the point they don't use "he" but rather "it". It appears as a formless vapor and did exactly what Ganon did in LoZ- ravaged Hyrule and made it a ruinous landscape. This makes me think, due to the formless and demonic nature of Ganon, that this Calamity Ganon is the purest remnant of a Ganon that has died- which would leave only Post WW, Post TP, or post LoZ (arguably post ALttP or ALBW even though those get wrapped up nicely). Combine this with the point about this needing to take place after any master sword game, and the Master Sword doing a little dance with Ariel under the sea in the AT, and we have this game being able to be nothing less than Zelda 3. This would also rule out it being post FSA in HH's version of the timeline since according to that timeline Ganon is sealed, not dead.
The HUGE scale can also be explained by both Link's wish at the end of AoL and the Hylian Empire theory, which is that Hyrule expanded it's territory in the NES games (backed up by LoZ's manual and LoZ Hyrule being only a small area of AoL)
Furthermore, it's possible the Link they resurrected is Skyward Sword Link, since he became the King of Hyrule eventually, and BotW Link is right handed. If this is a previous Link, SKYWARD SWORD LINK IS THE ONLY LINK WHO IS CANONICALLY RIGHT HANDED, unless ambidexterity is involved.
The apacolyptic nature of the game also makes putting BotW prior to ANY game a hard sell since Nintendo would have to clean everything up and pretend it never happened at the end.