The vaccines do not prevent you from getting Covid, but they lessen the effects of it (just like a flu vaccine).
Most people who get the vaccine also take other precautions (mask wearing, social distancing, hand washing, etc) and all that lessens the chance of getting sick. So, by practicing those precautions and getting vaccinated, the chance of getting seriously ill with Covid is greatly reduced - but not completely eliminated.
People who don't get the vaccine (unless for medical reasons) are less likely to practice those other precautions so have a greater chance of catching the virus AND getting seriously sick with it.
Yes, you can get vaccinated, take precautions, and still get sick. One interaction with an infected person can pass it to you. If you have other health issues, Covid can aggravate those.
I had a friend who died after his diabetes went haywire. It had been under control for over a year before this happened. What changed? He got Covid. The covid virus caused his diabetes to go uncontrollable. He was vaccinated and had the booster shot. Which did he die of? Both. Just like my dad who had diabetes and CHF. The CHF caused his diabetes to go oncontrollable and that caused his death.
This is why the CDC has been so vocal about protecting those with underlying health conditions - because Covid WILL affect those conditions.
I still wear a mask when I am in shops, etc. I do so to reduce the chance that I will catch the virus. But it's more than that - if I have a simple flu or cold and expose someone else to that, I could unintentionally make them more succeptible to Covid.
I do agree with the thought that "if it's my time to go", but that doesn't mean I am careless. I don't play Russian roulette with my life. I enjoy my life, but I don't take silly risks.
OP - I think you have a good mindset. Take your journey, continue to use precautions, and if you see something that makes you uncomfortable, walk/drive away. Don't hide in fear, but don't ignore common sense and don't take silly chances.