Chief is useless without constant weapons being dropped for ammo pickups, and doesn’t move well in water.
Doom Slayer is faster and stronger, and glory kills massive demons using melee attacks, as well as being able to quickly swim, dash, and punch through walls underwater.
Samus has the highest chance to win, since she has nearly infinite ammo, missiles, super missiles, bombs, power bombs, grapple, x-ray, ice beam, wave beam, and is completely invincible while running and jumping with screw attack, she could essentially fly with space jump, and can move at full speed in water and lava. On top of that, she can have up to 20 health bars, reserve tanks that refill 4 of them, and use a Power Bomb to Crystal Flash, refilling all her health tanks, and her reserve tanks. She has way too much health. If she can do a Crystal Flash, she basically has 5000 HP or more. After Other M, she also learned to replenish Missiles and HP by just concentrating and meditating. How does that work? No clue. Alien magic.
Isaac… Bro is literally just some guy with no genetic advantages. The other 3 have massive genetic advantages, and decades of combat training.