Sorry for your losses. They aren't pets, they are family. It is always hard losing someone you love.
You gave them a good and loving home and life.
They were spoiled, happy little guys until age took their health. I’m thankful that we are allowed to artificially end their suffering, and give them peace. I’d wish that for humans, but there are those who would exploit that for selfish reasons. Pets teach us empathy and compassion, I wouldn’t give that up to prevent the pain of loss.
We all take different paths but our end is the same. Be happy for the memories you have and the love given and given to you. You are a good person for giving them a good life.