In order to counteract "the snap" in Avengers: Infinity War, in Avengers: Endgame Tony Stark:
- Invents and constructs a workable time-travel device, and
- Joins other unsnapped Avengers in traveling back in time to "borrow" the infinity stones from the past (called a "time heist" in the movie).
This inadvertently results in 2014 Thanos coming to attack the present-day Avengers wherein present-day Tony Stark dies, and everyone is upset about it.
However, Tony Stark struggles with the idea of risking death to reverse the snap after getting a "second chance" to return to his family (wife and daughter). It seems to me that after constructing the time-travel device, Tony Stark no longer needs to participate in risky activities---he could let the others handle it from there.
Question: After constructing the time-travel device, couldn't Tony Stark let the other Avengers perform the "time heist"?
I don't see a reason this is infeasible or out of character, but maybe there's something I'm missing.