The deaths in IW1 are meaningless to the MCU as a whole, beyond being plot points for the IW movies.
At the end of IW2, they'll have defeated the big bad, and likely have 6 infinity stones at their disposal. Any actors that had their characters die in this film or the next film will be back to life for as many sequels as they want. To me, that's kind of the biggest let down of SO many characters dying, is you realistically know that most if not all of them will be brought back by the end of IW2.
But that's just comic books. We need the ability to have heroes lose, in order to tell stories that have any semblance of meaning. But we need the ability to re-boot/resurrect characters to tell new stories. That's just the way it works.