Finally got to watch the finale. I liked the ending a lot, very bittersweet.
Apparently at one point there was a line in the AoS finale regarding the Snap that was cut for time, but it's not clear that it was actually filmed or not. Even the showrunners don't seem especially clear on what the implications would have been for the AoS characters or overall MCU continuity:
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Did the altered timelines in "S.H.I.E.L.D." actually shift time enough to enable events in "Infinity War" and "Endgame"? Did the show ultimately reconnect with the Marvel movies in the end? Some of the Time Stream is melting my brain.
TANCHAROEN Melting brains is what we do. I'm still confused a bit, too.
WHEDON Some of the stuff they did with time travel in "Endgame" indicated that there are other timelines where other adventures are occurring. We're following the multi-verse rule. The only way that someone survives Thanos's snap in the movies is go into the quantum realm, and we originally did plan to give that a mention — because we used the quantum realm to move between timelines — but it got cut for time."
So either the AoS finale ends up as/always was its own "other timeline" where "other adventures are occurring" in the MCU Multi-verse, and/or Thanos's Snap happened to coincide with their trip through the Quantum Realm (a major retcon, since it would be at odds with the timing as presented in other episodes) or they were always travelling through the Quantum Realm when utilizing the Time Monolith and we just didn't know, putting the Snap during one of those trips, or that traveling through the QR itself affords some kind of protection against the Snap. The "other timeline" theory would explain why the effects of the Snap were never shown, while the QR aspect would only explain why none of the agents ended up Snapped. Oh well.