BG3 uses D20 rolls to hit. The lowest percentage increment is 5%. If you have a 95% chance to hit in BG3 and you miss, it means you rolled a 1.
Also, turn off karmic dice. They break success streaks as well as failure streaks, so once you're hitting most of the time it actually works against you.
I've had more luck so far getting good throws in BG3 than I had for anything else in my entire life. Which isn't a high bar, but it's a bar nonetheless.