A Normal guy dies in 2025 saving a innocent child from a speeding out of control car, and I giving a gift from a god of the multiverse. He is reborn in the Arrowverse as Oliver Queen but with three advantages and two reality chances that don't change the time line.
The first advantage is he as the perfected Captain America Super Soldier Serum and the military experience and combat experience of the Winter Soldier. The second advantage is the skills and abilities of Marvels Bullseye. And the third advantage is eidetic memory of both his life's.
As for the two reality chances he chooses that Sara Lance was always a devoted lesbian and was on the Queen's Gambit because she was interning with Robert Queen. The second change was to make John Diggile and Felicity Smoke meta humans Jon with the abilities of Luke Cage and Felicity with the abilities of Daisy Johnson Quake.