An mcu fan theory

out of 14 million outcomes dr strange saw in infinity war this is an outcome when tony stark refuse to snap the only one outcome avengers win as dr strange said is endgame it all make sense the mind stones power given to scarlett  witch showed the avengers an alternative time line in which they lost
which means multiverse  already exists in MCU right from the beginning we just didnt see it directly (just a fan theory)
Once carefully see this video