You are acting like AC doesn't exist. Attacks aren't automatic hits.
5e. Fighter and cleric, level 1, facing 4 goblins. Fighter has choice. Rush and attack at close range or attack at long. What is cleric's options? Rush and attack at close range or attack at long or buff them both with Bless. Hmmm. Cleric actually has more than I'm just a healer option.
Both rush forward. Both have AC 17. Fighter moves and attacks. Deals 1d8+2 damage. Goblin 1 has 3 HP left. Cleric moves and attacks Goblin 2. Misses. Goblins attack. Wow!. Let's say lucky round for goblins. 2 hit the fighter. They do 8 damage. DANG! Level 1 fighter is hurting. 2 HP left.
Round 2. Fighter has a choice. Potion or fight. He's got a good chance of not being hit again. 17 or higher is actually hard to do. He chances it. Fighter swings and hits, risking it. Goblin 1 dies. Cleric's turn. Should he use Cure Wounds or Healing Word to help the fighter. If Cure Wounds, more effective but no attack then. Uses Healing Word so he can still attack. Heals 6 HP. Ah. Now he has 8 HP. He swings and hits. 4 damage. Goblins attack, teaming up on fighter. They all miss.
Round 3. Both fighter and cleric attack. Miss. Goblins attack. Fighter is down. Cleric remains.
Round 4. Cleric uses Healing Word and heals 9 HP. Fighter has lost his turn. Goblins attack and miss.
Round 5. Fighter hits. Cleric swings and misses. Goblins attack and miss.
Round 6. Fighter hits. Goblin dies. Cleric hits. Goblin dies. Goblin hits cleric. Cleric has 1 HP.
Round 7. Fighter attacks. Misses. Cleric drinks potion. Heals 5 HP. Dang, that was close. No attack because potion is Action. Goblin swings and hits. Cleric down to 1 HP.
Round 8. Fighter hits. Cleric has choice. Heal or attack. Should he risk it? What strategy should he use? How many potions does he have? He goes for it and finishes off the goblin. Dang! That was close.
Excitement. Risk. Strategy. Near death.
Now. BG3 version.
Round 1. Same as above. Round 2. Fighter uses potion to heal as Bonus. 5 HP restored. Attacks. Hits. Kills Goblin 1. No brainer. Got like 6 potions. Why not? Cleric doesn't need to heal. Well, guess he'll attack. Bonus is free. Why not Shield of Faith it. He sees goblins are attacking fighter, so he casts in on Fighter. AC is now 19. He swings and hits goblin. 4 damage. Goblins attack, teaming up on fighter. They all miss.
Round 3. Both fighter and cleric attack. Miss. Goblins attack. Cleric is down. Fighter remains.
Round 4. Fighter throws potion and heals cleric 4 HP. He then uses his sword's pommel attack, which is a Bonus. Cleric uses potion as Bonus and is full health and then attacks. Goblin dies.
Round 5. Fighter hits. Cleric uses Bless. Goblins attack and miss.
Round 6. Fighter hits. Goblin dies. Cleric hits. Goblin dies. Thanks cleric for the buff. Battle ends.
In 5e, both cleric and the fighter had some rough choices at various times.
BG3, hardly a concerning fight. Not much risk involved.
