I'm guessing they break the Gauntlet somehow and each MCU-founding Avenger gets to use a stone. They do some Thanos-killing, reality-remaking shenanigans which essentially results in giving their life essence to the stone.
Time - for the man out of time
Space - for the god from space
Power - for the strongest one there is
Soul - for the woman without a soul
Mind - for the world's greatest mind
Reality - and I guess some guy named Clint
And they don't "die" after but maybe merge with the stones and become their ethereal guardians, like an Infinity Watch