2.0 vs 3.0 A6

Hello everyone I will be buying my first car shortly and I’m deciding on a A6 3.0 or a 2.0 trying to figure out which one would be a better fit for me I also want to know which engine is better reliability wise my mom has a q5 2.0 with 70k no problems (knock on wood) but I’m just trying to see what would be a better fit thank you