OK I got him out but it still doesn't answer the underlying question: Am I the only one who misses the majority of the time or is everyone having this issue, and if I am the only one, does anyone have any idea what I'm doing wrong?
A variety of people have expressed frustration at the amount of missing, but everyone's experiences greatly vary and depend on their tactics in game. The die rolls in BG3 seem roughly balanced in the long-term but very prone to streaks.
- What are your typical chances to hit? If you are missing 70% of the time and you typically have a 30% chance to hit, then that makes sense. You should typically have a 60-90% chance to hit.
- Are you making use of Advantage? Ranged attacks from high ground and melee attacking the enemy's back grants Advantage which increases your chances to hit.
- What weapons are you using? Are you proficient in them? Are they making use of the best stat? Ranged weapons and finesse melee weapons are better for high-dex characters, all other weapons are better for high-strength characters. Using a weapon that your character is not proficient in (a different mechanic than str vs dex) effectively imposes a 15% to-hit penalty.
- Are you often attacking with Disadvantage? Disadvantage is most often granted if the enemy is unlit and your character doesn't have darkvision, or if you're attacking from low ground. For the former, use torches or spells that grant light. For the latter, go to high ground.
- What kind of spells are you using? Some are much better than others. Shadowheart's Sacred Flame, for example, is basically useless because it targets enemy's saving throws (and thus doesn't benefit from Advantage's bonus to-hit) and deals little damage. Some spells are guaranteed to hit, some require your character to make an attack roll, some target different enemy's saves. Some spells just deal more damage than others.
- Are you using any types of buffs/debuffs? The Bless spell can help your characters hit enemies by providing a +1d4 bonus to attack rolls. Mirror image and Blur make it more difficult for the enemy to hit you. Potions of speed give your characters extra actions for a couple turns.
I'll echo what @fallenj said about how to see your % chance to hit and also reading the combat log for more information.
Edit: you just posted saying you usually have a 45% chance to hit. This is very low. See my comments above on gaining Advantage (adds 15-25% to-hit), not having disadvantage (which subtracts 15-25% to hit), and ensuring you're using proper weapons.
