Qual é o status dos Infinity Stones após Vingadores: Ultimato?

NOTE: this answer is totally wrong! The Russo brothers have confirmed that alternate realities are created without removing Infinity Stones from the timeline.

It just means that there's now an alternative timeline kicking off in 2014 in which Nebula and Thanos don't exist.

Just like in the movie itself, people love to confidently state how time travel works, despite the fact that it's an entirely fictional concept, and thus works exactly how the authors of any story decide it works, regardless of your own conception of temporal logic.

The movie goes to considerable effort to explain its time travel rules, including the alternative timeline question. The Ancient One even draws us a picture. Here's what she tells us:

• The Infinity Stones (as a whole) are responsible for creating the flow of time in the universe.
• If you remove an Infinity Stone from the timeline via time travel, an alternative reality will be created, without that stone in it. This would be ruim for that reality.
• By implication, aside from that, time travel does não create ongoing alternate realities, yet does not affect the past, or the present.

So, after Cap returns the Infinity Stones to their original places in the timeline, everything is fine, and still happens in the way we saw it happen. Thus the Infinity Stones are eventually used to destroy themselves in Thanos' garden. (For some reason, this is presumably fine for the universe, even though the stones are apparently responsible for creating its flow of time.)

I'm not saying it makes sense! I'm just saying this is how the movie tells us it works.

The status of the Infinity Stones in my mind is quite simple, the ones from the past are back in the past returned as they were taken so that the timeline doesn't spawn alternate timelines as explained by The Ancient One. The ones in the future are still destroyed as Thanos had destroyed them, assuming he wasn't lying of course, which I don't think he was considering past Thanos' comments about it.

It just means that there's now an alternative timeline kicking off in 2014 in which Nebula and Thanos don't exist.

FWIW I think this statement in the article is wrong, there is no alternative timeline starting in 2014 because the Infinity Stones were placed back where they came from.

As for whether Doctor Strange would be concerned about losing the Time Stone, probably not really. He is concerned about keeping the universe alive and losing the Time Stone is a small price to pay for that.

The Russo’s have confirmed the infinity stones are not destroyed at all. Thanos just reduces them to atoms but they still exist in the MCU

https://www.google.com/amp/s/screenrant.com/avengers-endgame-director-russos-infinity-stones-still-exist/amp/