I do hope you recovered quickly. I know some people that received the vaccine still managed to get COVID. However, my understanding is that these cases were generally milder and of shorter duration.
I am taking Hydroxyurea for ET and apparently at high risk for COVID and nasty complications (also in my 80’s).My husband is in his 80’s type 2 diabetic and also at high risk. Despite the having all the vaccine recommended, we still were careful about masking, where we went etc. We got through with no problems, managed lunches out at parks, camped with our camper and kept ourselves busy. Missed some family visits but we were fine in most ways.

There are no vaccines that are 100% effective. That kind of certainty does not exist in the real world. I think I read that when the FDA evaluates vaccines, if they prevent disease in 50% of the population, then they will proceed with it. The Covid vaccine is known to reduce the severity of illness if you do get it. If you were not hospitalized and did not die, count that as a win.

My transplant specialist emphasized to me that if I feel sick, see my doctor right away, even if a Covid antigen test is negative. For people in my situation, Covid is worse than for people in general. There are drugs now that can help.

The latest Covid-19 vaccine provides protection against the latest variant. I got it as soon as it became available.

As an employee of HHS I often get emails about public health topics. Here is a short video from the head of the Centers for Disease Control about the latest Covid vaccine.